cmake-commands(7)
*****************

Scripting Commands
==================

These commands are always available.

break
-----

Break from an enclosing foreach or while loop.

::

 break()

Breaks from an enclosing foreach loop or while loop

See also the ``continue()`` command.

cmake_host_system_information
-----------------------------

Query host system specific information.

::

 cmake_host_system_information(RESULT <variable> QUERY <key> ...)

Queries system information of the host system on which cmake runs.
One or more ``<key>`` can be provided to select the information to be
queried.  The list of queried values is stored in ``<variable>``.

``<key>`` can be one of the following values:

::

 NUMBER_OF_LOGICAL_CORES   = Number of logical cores.
 NUMBER_OF_PHYSICAL_CORES  = Number of physical cores.
 HOSTNAME                  = Hostname.
 FQDN                      = Fully qualified domain name.
 TOTAL_VIRTUAL_MEMORY      = Total virtual memory in megabytes.
 AVAILABLE_VIRTUAL_MEMORY  = Available virtual memory in megabytes.
 TOTAL_PHYSICAL_MEMORY     = Total physical memory in megabytes.
 AVAILABLE_PHYSICAL_MEMORY = Available physical memory in megabytes.

cmake_minimum_required
----------------------

Set the minimum required version of cmake for a project and
update `Policy Settings`_ to match the version given::

 cmake_minimum_required(VERSION major.minor[.patch[.tweak]]
                        [FATAL_ERROR])

If the current version of CMake is lower than that required it will
stop processing the project and report an error.

The ``FATAL_ERROR`` option is accepted but ignored by CMake 2.6 and
higher.  It should be specified so CMake versions 2.4 and lower fail
with an error instead of just a warning.

.. note::
  Call the ``cmake_minimum_required()`` command at the beginning of
  the top-level ``CMakeLists.txt`` file even before calling the
  ``project()`` command.  It is important to establish version
  and policy settings before invoking other commands whose behavior
  they may affect.  See also policy ``CMP0000``.

  Calling ``cmake_minimum_required()`` inside a ``function()``
  limits some effects to the function scope when invoked.  Such calls
  should not be made with the intention of having global effects.

Policy Settings
^^^^^^^^^^^^^^^

The ``cmake_minimum_required(VERSION)`` command implicitly invokes the
``cmake_policy(VERSION)`` command to specify that the current
project code is written for the given version of CMake.
All policies introduced in the specified version or earlier will be
set to use NEW behavior.  All policies introduced after the specified
version will be unset.  This effectively requests behavior preferred
as of a given CMake version and tells newer CMake versions to warn
about their new policies.

When a version higher than 2.4 is specified the command implicitly
invokes::

 cmake_policy(VERSION major[.minor[.patch[.tweak]]])

which sets the cmake policy version level to the version specified.
When version 2.4 or lower is given the command implicitly invokes::

 cmake_policy(VERSION 2.4)

which enables compatibility features for CMake 2.4 and lower.

cmake_parse_arguments
---------------------

``cmake_parse_arguments`` is intended to be used in macros or functions for
parsing the arguments given to that macro or function.  It processes the
arguments and defines a set of variables which hold the values of the
respective options.

::

 cmake_parse_arguments(<prefix> <options> <one_value_keywords>
                       <multi_value_keywords> args...)

 cmake_parse_arguments(PARSE_ARGV N <prefix> <options> <one_value_keywords>
                       <multi_value_keywords>)

The first signature reads processes arguments passed in the ``args...``.
This may be used in either a ``macro()`` or a ``function()``.

The ``PARSE_ARGV`` signature is only for use in a ``function()``
body.  In this case the arguments that are parsed come from the
``ARGV#`` variables of the calling function.  The parsing starts with
the Nth argument, where ``N`` is an unsigned integer.  This allows for
the values to have special characters like ``;`` in them.

The ``<options>`` argument contains all options for the respective macro,
i.e.  keywords which can be used when calling the macro without any value
following, like e.g.  the ``OPTIONAL`` keyword of the ``install()``
command.

The ``<one_value_keywords>`` argument contains all keywords for this macro
which are followed by one value, like e.g. ``DESTINATION`` keyword of the
``install()`` command.

The ``<multi_value_keywords>`` argument contains all keywords for this
macro which can be followed by more than one value, like e.g. the
``TARGETS`` or ``FILES`` keywords of the ``install()`` command.

.. note::

   All keywords shall be unique. I.e. every keyword shall only be specified
   once in either ``<options>``, ``<one_value_keywords>`` or
   ``<multi_value_keywords>``. A warning will be emitted if uniqueness is
   violated.

When done, ``cmake_parse_arguments`` will have defined for each of the
keywords listed in ``<options>``, ``<one_value_keywords>`` and
``<multi_value_keywords>`` a variable composed of the given ``<prefix>``
followed by ``"_"`` and the name of the respective keyword.  These
variables will then hold the respective value from the argument list.
For the ``<options>`` keywords this will be ``TRUE`` or ``FALSE``.

All remaining arguments are collected in a variable
``<prefix>_UNPARSED_ARGUMENTS``, this can be checked afterwards to see
whether your macro was called with unrecognized parameters.

As an example here a ``my_install()`` macro, which takes similar arguments
as the real ``install()`` command:

 function(MY_INSTALL)
     set(options OPTIONAL FAST)
     set(oneValueArgs DESTINATION RENAME)
     set(multiValueArgs TARGETS CONFIGURATIONS)
     cmake_parse_arguments(MY_INSTALL "${options}" "${oneValueArgs}"
                           "${multiValueArgs}" ${ARGN} )

     # ...

Assume ``my_install()`` has been called like this:

 my_install(TARGETS foo bar DESTINATION bin OPTIONAL blub)

After the ``cmake_parse_arguments`` call the macro will have set the
following variables::

 MY_INSTALL_OPTIONAL = TRUE
 MY_INSTALL_FAST = FALSE (was not used in call to my_install)
 MY_INSTALL_DESTINATION = "bin"
 MY_INSTALL_RENAME = "" (was not used)
 MY_INSTALL_TARGETS = "foo;bar"
 MY_INSTALL_CONFIGURATIONS = "" (was not used)
 MY_INSTALL_UNPARSED_ARGUMENTS = "blub" (nothing expected after "OPTIONAL")

You can then continue and process these variables.

Keywords terminate lists of values, e.g.  if directly after a
one_value_keyword another recognized keyword follows, this is
interpreted as the beginning of the new option.  E.g.
``my_install(TARGETS foo DESTINATION OPTIONAL)`` would result in
``MY_INSTALL_DESTINATION`` set to ``"OPTIONAL"``, but as ``OPTIONAL``
is a keyword itself ``MY_INSTALL_DESTINATION`` will be empty and
``MY_INSTALL_OPTIONAL`` will therefore be set to ``TRUE``.

cmake_policy
------------

Manage CMake Policy settings.  See the ``cmake-policies(7)``
manual for defined policies.

As CMake evolves it is sometimes necessary to change existing behavior
in order to fix bugs or improve implementations of existing features.
The CMake Policy mechanism is designed to help keep existing projects
building as new versions of CMake introduce changes in behavior.  Each
new policy (behavioral change) is given an identifier of the form
``CMP<NNNN>`` where ``<NNNN>`` is an integer index.  Documentation
associated with each policy describes the ``OLD`` and ``NEW`` behavior
and the reason the policy was introduced.  Projects may set each policy
to select the desired behavior.  When CMake needs to know which behavior
to use it checks for a setting specified by the project.  If no
setting is available the ``OLD`` behavior is assumed and a warning is
produced requesting that the policy be set.

Setting Policies by CMake Version
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The ``cmake_policy`` command is used to set policies to ``OLD`` or ``NEW``
behavior.  While setting policies individually is supported, we
encourage projects to set policies based on CMake versions::

 cmake_policy(VERSION major.minor[.patch[.tweak]])

Specify that the current CMake code is written for the given
version of CMake.  All policies introduced in the specified version or
earlier will be set to use ``NEW`` behavior.  All policies introduced
after the specified version will be unset (unless the
``CMAKE_POLICY_DEFAULT_CMP<NNNN>`` variable sets a default).
This effectively requests behavior preferred as of a given CMake
version and tells newer CMake versions to warn about their new policies.
The policy version specified must be at least 2.4 or the command will
report an error.

Note that the ``cmake_minimum_required(VERSION)``
command implicitly calls ``cmake_policy(VERSION)`` too.

Setting Policies Explicitly
^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 cmake_policy(SET CMP<NNNN> NEW)
 cmake_policy(SET CMP<NNNN> OLD)

Tell CMake to use the ``OLD`` or ``NEW`` behavior for a given policy.
Projects depending on the old behavior of a given policy may silence a
policy warning by setting the policy state to ``OLD``.  Alternatively
one may fix the project to work with the new behavior and set the
policy state to ``NEW``.

.. note::
  The ``OLD`` behavior of a policy is
  ``deprecated by definition``
  and may be removed in a future version of CMake.

Checking Policy Settings
^^^^^^^^^^^^^^^^^^^^^^^^

::

 cmake_policy(GET CMP<NNNN> <variable>)

Check whether a given policy is set to ``OLD`` or ``NEW`` behavior.
The output ``<variable>`` value will be ``OLD`` or ``NEW`` if the
policy is set, and empty otherwise.

CMake Policy Stack
^^^^^^^^^^^^^^^^^^

CMake keeps policy settings on a stack, so changes made by the
cmake_policy command affect only the top of the stack.  A new entry on
the policy stack is managed automatically for each subdirectory to
protect its parents and siblings.  CMake also manages a new entry for
scripts loaded by ``include()`` and ``find_package()`` commands
except when invoked with the ``NO_POLICY_SCOPE`` option
(see also policy ``CMP0011``).
The ``cmake_policy`` command provides an interface to manage custom
entries on the policy stack::

 cmake_policy(PUSH)
 cmake_policy(POP)

Each ``PUSH`` must have a matching ``POP`` to erase any changes.
This is useful to make temporary changes to policy settings.
Calls to the ``cmake_minimum_required(VERSION)``,
``cmake_policy(VERSION)``, or ``cmake_policy(SET)`` commands
influence only the current top of the policy stack.

Commands created by the ``function()`` and ``macro()``
commands record policy settings when they are created and
use the pre-record policies when they are invoked.  If the function or
macro implementation sets policies, the changes automatically
propagate up through callers until they reach the closest nested
policy stack entry.

configure_file
--------------

Copy a file to another location and modify its contents.

::

 configure_file(<input> <output>
                [COPYONLY] [ESCAPE_QUOTES] [@ONLY]
                [NEWLINE_STYLE [UNIX|DOS|WIN32|LF|CRLF] ])

Copies an ``<input>`` file to an ``<output>`` file and substitutes
variable values referenced as ``@VAR@`` or ``${VAR}`` in the input
file content.  Each variable reference will be replaced with the
current value of the variable, or the empty string if the variable
is not defined.  Furthermore, input lines of the form::

 #cmakedefine VAR ...

will be replaced with either::

 #define VAR ...

or::

 /* #undef VAR */

depending on whether ``VAR`` is set in CMake to any value not considered
a false constant by the ``if()`` command.  The "..." content on the
line after the variable name, if any, is processed as above.
Input file lines of the form ``#cmakedefine01 VAR`` will be replaced with
either ``#define VAR 1`` or ``#define VAR 0`` similarly.

If the input file is modified the build system will re-run CMake to
re-configure the file and generate the build system again.

The arguments are:

``<input>``
  Path to the input file.  A relative path is treated with respect to
  the value of ``CMAKE_CURRENT_SOURCE_DIR``.  The input path
  must be a file, not a directory.

``<output>``
  Path to the output file or directory.  A relative path is treated
  with respect to the value of ``CMAKE_CURRENT_BINARY_DIR``.
  If the path names an existing directory the output file is placed
  in that directory with the same file name as the input file.

``COPYONLY``
  Copy the file without replacing any variable references or other
  content.  This option may not be used with ``NEWLINE_STYLE``.

``ESCAPE_QUOTES``
  Escape any substituted quotes with backslashes (C-style).

``@ONLY``
  Restrict variable replacement to references of the form ``@VAR@``.
  This is useful for configuring scripts that use ``${VAR}`` syntax.

``NEWLINE_STYLE <style>``
  Specify the newline style for the output file.  Specify
  ``UNIX`` or ``LF`` for ``\n`` newlines, or specify
  ``DOS``, ``WIN32``, or ``CRLF`` for ``\r\n`` newlines.
  This option may not be used with ``COPYONLY``.

Example
^^^^^^^

Consider a source tree containing a ``foo.h.in`` file:

 #cmakedefine FOO_ENABLE
 #cmakedefine FOO_STRING "@FOO_STRING@"

An adjacent ``CMakeLists.txt`` may use ``configure_file`` to
configure the header:

 option(FOO_ENABLE "Enable Foo" ON)
 if(FOO_ENABLE)
   set(FOO_STRING "foo")
 endif()
 configure_file(foo.h.in foo.h @ONLY)

This creates a ``foo.h`` in the build directory corresponding to
this source directory.  If the ``FOO_ENABLE`` option is on, the
configured file will contain:

 #define FOO_ENABLE
 #define FOO_STRING "foo"

Otherwise it will contain:

 /* #undef FOO_ENABLE */
 /* #undef FOO_STRING */

One may then use the ``include_directories()`` command to
specify the output directory as an include directory:

 include_directories(${CMAKE_CURRENT_BINARY_DIR})

so that sources may include the header as ``#include <foo.h>``.

continue
--------

Continue to the top of enclosing foreach or while loop.

::

 continue()

The ``continue`` command allows a cmake script to abort the rest of a block
in a ``foreach()`` or ``while()`` loop, and start at the top of
the next iteration.  See also the ``break()`` command.

elseif
------

Starts the elseif portion of an if block.

::

 elseif(expression)

See the ``if()`` command.

else
----

Starts the else portion of an if block.

::

 else(expression)

See the ``if()`` command.

endforeach
----------

Ends a list of commands in a foreach block.

::

 endforeach(expression)

See the ``foreach()`` command.

endfunction
-----------

Ends a list of commands in a function block.

::

 endfunction(expression)

See the ``function()`` command.

endif
-----

Ends a list of commands in an if block.

::

 endif(expression)

See the ``if()`` command.

endmacro
--------

Ends a list of commands in a macro block.

::

 endmacro(expression)

See the ``macro()`` command.

endwhile
--------

Ends a list of commands in a while block.

::

 endwhile(expression)

See the ``while()`` command.

execute_process
---------------

Execute one or more child processes.

 execute_process(COMMAND <cmd1> [args1...]]
                 [COMMAND <cmd2> [args2...] [...]]
                 [WORKING_DIRECTORY <directory>]
                 [TIMEOUT <seconds>]
                 [RESULT_VARIABLE <variable>]
                 [OUTPUT_VARIABLE <variable>]
                 [ERROR_VARIABLE <variable>]
                 [INPUT_FILE <file>]
                 [OUTPUT_FILE <file>]
                 [ERROR_FILE <file>]
                 [OUTPUT_QUIET]
                 [ERROR_QUIET]
                 [OUTPUT_STRIP_TRAILING_WHITESPACE]
                 [ERROR_STRIP_TRAILING_WHITESPACE]
                 [ENCODING <name>])

Runs the given sequence of one or more commands in parallel with the standard
output of each process piped to the standard input of the next.
A single standard error pipe is used for all processes.

Options:

``COMMAND``
 A child process command line.

 CMake executes the child process using operating system APIs directly.
 All arguments are passed VERBATIM to the child process.
 No intermediate shell is used, so shell operators such as ``>``
 are treated as normal arguments.
 (Use the ``INPUT_*``, ``OUTPUT_*``, and ``ERROR_*`` options to
 redirect stdin, stdout, and stderr.)

 If a sequential execution of multiple commands is required, use multiple
 ``execute_process()`` calls with a single ``COMMAND`` argument.

``WORKING_DIRECTORY``
 The named directory will be set as the current working directory of
 the child processes.

``TIMEOUT``
 The child processes will be terminated if they do not finish in the
 specified number of seconds (fractions are allowed).

``RESULT_VARIABLE``
 The variable will be set to contain the result of running the processes.
 This will be an integer return code from the last child or a string
 describing an error condition.

``OUTPUT_VARIABLE``, ``ERROR_VARIABLE``
 The variable named will be set with the contents of the standard output
 and standard error pipes, respectively.  If the same variable is named
 for both pipes their output will be merged in the order produced.

``INPUT_FILE, OUTPUT_FILE``, ``ERROR_FILE``
 The file named will be attached to the standard input of the first
 process, standard output of the last process, or standard error of
 all processes, respectively.  If the same file is named for both
 output and error then it will be used for both.

``OUTPUT_QUIET``, ``ERROR_QUIET``
 The standard output or standard error results will be quietly ignored.

``ENCODING <name>``
 On Windows, the encoding that is used to decode output from the process.
 Ignored on other platforms.
 Valid encoding names are:

 ``NONE``
   Perform no decoding.  This assumes that the process output is encoded
   in the same way as CMake's internal encoding (UTF-8).
   This is the default.
 ``AUTO``
   Use the current active console's codepage or if that isn't
   available then use ANSI.
 ``ANSI``
   Use the ANSI codepage.
 ``OEM``
   Use the original equipment manufacturer (OEM) code page.
 ``UTF8``
   Use the UTF-8 codepage.

If more than one ``OUTPUT_*`` or ``ERROR_*`` option is given for the
same pipe the precedence is not specified.
If no ``OUTPUT_*`` or ``ERROR_*`` options are given the output will
be shared with the corresponding pipes of the CMake process itself.

The ``execute_process()`` command is a newer more powerful version of
``exec_program()``, but the old command has been kept for compatibility.
Both commands run while CMake is processing the project prior to build
system generation.  Use ``add_custom_target()`` and
``add_custom_command()`` to create custom commands that run at
build time.

file
----

File manipulation command.

------------------------------------------------------------------------------

::

 file(WRITE <filename> <content>...)
 file(APPEND <filename> <content>...)

Write ``<content>`` into a file called ``<filename>``.  If the file does
not exist, it will be created.  If the file already exists, ``WRITE``
mode will overwrite it and ``APPEND`` mode will append to the end.
(If the file is a build input, use the ``configure_file()`` command
to update the file only when its content changes.)

------------------------------------------------------------------------------

::

 file(READ <filename> <variable>
      [OFFSET <offset>] [LIMIT <max-in>] [HEX])

Read content from a file called ``<filename>`` and store it in a
``<variable>``.  Optionally start from the given ``<offset>`` and
read at most ``<max-in>`` bytes.  The ``HEX`` option causes data to
be converted to a hexadecimal representation (useful for binary data).

------------------------------------------------------------------------------

::

 file(STRINGS <filename> <variable> [<options>...])

Parse a list of ASCII strings from ``<filename>`` and store it in
``<variable>``.  Binary data in the file are ignored.  Carriage return
(``\r``, CR) characters are ignored.  The options are:

``LENGTH_MAXIMUM <max-len>``
 Consider only strings of at most a given length.

``LENGTH_MINIMUM <min-len>``
 Consider only strings of at least a given length.

``LIMIT_COUNT <max-num>``
 Limit the number of distinct strings to be extracted.

``LIMIT_INPUT <max-in>``
 Limit the number of input bytes to read from the file.

``LIMIT_OUTPUT <max-out>``
 Limit the number of total bytes to store in the ``<variable>``.

``NEWLINE_CONSUME``
 Treat newline characters (``\n``, LF) as part of string content
 instead of terminating at them.

``NO_HEX_CONVERSION``
 Intel Hex and Motorola S-record files are automatically converted to
 binary while reading unless this option is given.

``REGEX <regex>``
 Consider only strings that match the given regular expression.

``ENCODING <encoding-type>``
 Consider strings of a given encoding.  Currently supported encodings are:
 UTF-8, UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE.  If the ENCODING option
 is not provided and the file has a Byte Order Mark, the ENCODING option
 will be defaulted to respect the Byte Order Mark.

For example, the code

 file(STRINGS myfile.txt myfile)

stores a list in the variable ``myfile`` in which each item is a line
from the input file.

------------------------------------------------------------------------------

::

 file(<HASH> <filename> <variable>)

Compute a cryptographic hash of the content of ``<filename>`` and
store it in a ``<variable>``.  The supported ``<HASH>`` algorithm names
are those listed by the :ref:`string(\<HASH\>) <Supported Hash Algorithms>`
command.

------------------------------------------------------------------------------

::

 file(GLOB <variable>
      [LIST_DIRECTORIES true|false] [RELATIVE <path>]
      [<globbing-expressions>...])
 file(GLOB_RECURSE <variable> [FOLLOW_SYMLINKS]
      [LIST_DIRECTORIES true|false] [RELATIVE <path>]
      [<globbing-expressions>...])

Generate a list of files that match the ``<globbing-expressions>`` and
store it into the ``<variable>``.  Globbing expressions are similar to
regular expressions, but much simpler.  If ``RELATIVE`` flag is
specified, the results will be returned as relative paths to the given
path.  No specific order of results is defined other than that it is
deterministic.  If order is important then sort the list explicitly
(e.g. using the ``list(SORT)`` command).

By default ``GLOB`` lists directories - directories are omited in result if
``LIST_DIRECTORIES`` is set to false.

.. note::
  We do not recommend using GLOB to collect a list of source files from
  your source tree.  If no CMakeLists.txt file changes when a source is
  added or removed then the generated build system cannot know when to
  ask CMake to regenerate.

Examples of globbing expressions include::

 *.cxx      - match all files with extension cxx
 *.vt?      - match all files with extension vta,...,vtz
 f[3-5].txt - match files f3.txt, f4.txt, f5.txt

The ``GLOB_RECURSE`` mode will traverse all the subdirectories of the
matched directory and match the files.  Subdirectories that are symlinks
are only traversed if ``FOLLOW_SYMLINKS`` is given or policy
``CMP0009`` is not set to ``NEW``.

By default ``GLOB_RECURSE`` omits directories from result list - setting
``LIST_DIRECTORIES`` to true adds directories to result list.
If ``FOLLOW_SYMLINKS`` is given or policy ``CMP0009`` is not set to
``OLD`` then ``LIST_DIRECTORIES`` treats symlinks as directories.

Examples of recursive globbing include::

 /dir/*.py  - match all python files in /dir and subdirectories

------------------------------------------------------------------------------

::

 file(RENAME <oldname> <newname>)

Move a file or directory within a filesystem from ``<oldname>`` to
``<newname>``, replacing the destination atomically.

------------------------------------------------------------------------------

::

 file(REMOVE [<files>...])
 file(REMOVE_RECURSE [<files>...])

Remove the given files.  The ``REMOVE_RECURSE`` mode will remove the given
files and directories, also non-empty directories. No error is emitted if a
given file does not exist.

------------------------------------------------------------------------------

::

 file(MAKE_DIRECTORY [<directories>...])

Create the given directories and their parents as needed.

------------------------------------------------------------------------------

::

 file(RELATIVE_PATH <variable> <directory> <file>)

Compute the relative path from a ``<directory>`` to a ``<file>`` and
store it in the ``<variable>``.

------------------------------------------------------------------------------

::

 file(TO_CMAKE_PATH "<path>" <variable>)
 file(TO_NATIVE_PATH "<path>" <variable>)

The ``TO_CMAKE_PATH`` mode converts a native ``<path>`` into a cmake-style
path with forward-slashes (``/``).  The input can be a single path or a
system search path like ``$ENV{PATH}``.  A search path will be converted
to a cmake-style list separated by ``;`` characters.

The ``TO_NATIVE_PATH`` mode converts a cmake-style ``<path>`` into a native
path with platform-specific slashes (``\`` on Windows and ``/`` elsewhere).

Always use double quotes around the ``<path>`` to be sure it is treated
as a single argument to this command.

------------------------------------------------------------------------------

::

 file(DOWNLOAD <url> <file> [<options>...])
 file(UPLOAD   <file> <url> [<options>...])

The ``DOWNLOAD`` mode downloads the given ``<url>`` to a local ``<file>``.
The ``UPLOAD`` mode uploads a local ``<file>`` to a given ``<url>``.

Options to both ``DOWNLOAD`` and ``UPLOAD`` are:

``INACTIVITY_TIMEOUT <seconds>``
  Terminate the operation after a period of inactivity.

``LOG <variable>``
  Store a human-readable log of the operation in a variable.

``SHOW_PROGRESS``
  Print progress information as status messages until the operation is
  complete.

``STATUS <variable>``
  Store the resulting status of the operation in a variable.
  The status is a ``;`` separated list of length 2.
  The first element is the numeric return value for the operation,
  and the second element is a string value for the error.
  A ``0`` numeric error means no error in the operation.

``TIMEOUT <seconds>``
  Terminate the operation after a given total time has elapsed.

``USERPWD <username>:<password>``
  Set username and password for operation.

``HTTPHEADER <HTTP-header>``
  HTTP header for operation. Suboption can be repeated several times.

Additional options to ``DOWNLOAD`` are:

``EXPECTED_HASH ALGO=<value>``

  Verify that the downloaded content hash matches the expected value, where
  ``ALGO`` is one of the algorithms supported by ``file(<HASH>)``.
  If it does not match, the operation fails with an error.

``EXPECTED_MD5 <value>``
  Historical short-hand for ``EXPECTED_HASH MD5=<value>``.

``TLS_VERIFY <ON|OFF>``
  Specify whether to verify the server certificate for ``https://`` URLs.
  The default is to *not* verify.

``TLS_CAINFO <file>``
  Specify a custom Certificate Authority file for ``https://`` URLs.

For ``https://`` URLs CMake must be built with OpenSSL support.  ``TLS/SSL``
certificates are not checked by default.  Set ``TLS_VERIFY`` to ``ON`` to
check certificates and/or use ``EXPECTED_HASH`` to verify downloaded content.
If neither ``TLS`` option is given CMake will check variables
``CMAKE_TLS_VERIFY`` and ``CMAKE_TLS_CAINFO``, respectively.

------------------------------------------------------------------------------

::

 file(TIMESTAMP <filename> <variable> [<format>] [UTC])

Compute a string representation of the modification time of ``<filename>``
and store it in ``<variable>``.  Should the command be unable to obtain a
timestamp variable will be set to the empty string ("").

See the ``string(TIMESTAMP)`` command for documentation of
the ``<format>`` and ``UTC`` options.

------------------------------------------------------------------------------

::

 file(GENERATE OUTPUT output-file
      <INPUT input-file|CONTENT content>
      [CONDITION expression])

Generate an output file for each build configuration supported by the current
``CMake Generator``.  Evaluate
``generator expressions``
from the input content to produce the output content.  The options are:

``CONDITION <condition>``
  Generate the output file for a particular configuration only if
  the condition is true.  The condition must be either ``0`` or ``1``
  after evaluating generator expressions.

``CONTENT <content>``
  Use the content given explicitly as input.

``INPUT <input-file>``
  Use the content from a given file as input.

``OUTPUT <output-file>``
  Specify the output file name to generate.  Use generator expressions
  such as ``$<CONFIG>`` to specify a configuration-specific output file
  name.  Multiple configurations may generate the same output file only
  if the generated content is identical.  Otherwise, the ``<output-file>``
  must evaluate to an unique name for each configuration.

Exactly one ``CONTENT`` or ``INPUT`` option must be given.  A specific
``OUTPUT`` file may be named by at most one invocation of ``file(GENERATE)``.
Generated files are modified on subsequent cmake runs only if their content
is changed.

Note also that ``file(GENERATE)`` does not create the output file until the
generation phase. The output file will not yet have been written when the
``file(GENERATE)`` command returns, it is written only after processing all
of a project's ``CMakeLists.txt`` files.

------------------------------------------------------------------------------

::

 file(<COPY|INSTALL> <files>... DESTINATION <dir>
      [FILE_PERMISSIONS <permissions>...]
      [DIRECTORY_PERMISSIONS <permissions>...]
      [NO_SOURCE_PERMISSIONS] [USE_SOURCE_PERMISSIONS]
      [FILES_MATCHING]
      [[PATTERN <pattern> | REGEX <regex>]
       [EXCLUDE] [PERMISSIONS <permissions>...]] [...])

The ``COPY`` signature copies files, directories, and symlinks to a
destination folder.  Relative input paths are evaluated with respect
to the current source directory, and a relative destination is
evaluated with respect to the current build directory.  Copying
preserves input file timestamps, and optimizes out a file if it exists
at the destination with the same timestamp.  Copying preserves input
permissions unless explicit permissions or ``NO_SOURCE_PERMISSIONS``
are given (default is ``USE_SOURCE_PERMISSIONS``).

See the ``install(DIRECTORY)`` command for documentation of
permissions, ``FILES_MATCHING``, ``PATTERN``, ``REGEX``, and
``EXCLUDE`` options.  Copying directories preserves the structure
of their content even if options are used to select a subset of
files.

The ``INSTALL`` signature differs slightly from ``COPY``: it prints
status messages (subject to the ``CMAKE_INSTALL_MESSAGE`` variable),
and ``NO_SOURCE_PERMISSIONS`` is default.
Installation scripts generated by the ``install()`` command
use this signature (with some undocumented options for internal use).

------------------------------------------------------------------------------

::

 file(LOCK <path> [DIRECTORY] [RELEASE]
      [GUARD <FUNCTION|FILE|PROCESS>]
      [RESULT_VARIABLE <variable>]
      [TIMEOUT <seconds>])

Lock a file specified by ``<path>`` if no ``DIRECTORY`` option present and file
``<path>/cmake.lock`` otherwise. File will be locked for scope defined by
``GUARD`` option (default value is ``PROCESS``). ``RELEASE`` option can be used
to unlock file explicitly. If option ``TIMEOUT`` is not specified CMake will
wait until lock succeed or until fatal error occurs. If ``TIMEOUT`` is set to
``0`` lock will be tried once and result will be reported immediately. If
``TIMEOUT`` is not ``0`` CMake will try to lock file for the period specified
by ``<seconds>`` value. Any errors will be interpreted as fatal if there is no
``RESULT_VARIABLE`` option. Otherwise result will be stored in ``<variable>``
and will be ``0`` on success or error message on failure.

Note that lock is advisory - there is no guarantee that other processes will
respect this lock, i.e. lock synchronize two or more CMake instances sharing
some modifiable resources. Similar logic applied to ``DIRECTORY`` option -
locking parent directory doesn't prevent other ``LOCK`` commands to lock any
child directory or file.

Trying to lock file twice is not allowed.  Any intermediate directories and
file itself will be created if they not exist.  ``GUARD`` and ``TIMEOUT``
options ignored on ``RELEASE`` operation.

find_file
---------

A short-hand signature is:

 find_file (<VAR> name1 [path1 path2 ...])

The general signature is:

 find_file (
           <VAR>
           name | NAMES name1 [name2 ...]
           [HINTS path1 [path2 ... ENV var]]
           [PATHS path1 [path2 ... ENV var]]
           [PATH_SUFFIXES suffix1 [suffix2 ...]]
           [DOC "cache documentation string"]
           [NO_DEFAULT_PATH]
           [NO_CMAKE_PATH]
           [NO_CMAKE_ENVIRONMENT_PATH]
           [NO_SYSTEM_ENVIRONMENT_PATH]
           [NO_CMAKE_SYSTEM_PATH]
           [CMAKE_FIND_ROOT_PATH_BOTH |
            ONLY_CMAKE_FIND_ROOT_PATH |
            NO_CMAKE_FIND_ROOT_PATH]
          )

This command is used to find a full path to named file.
A cache entry named by ``<VAR>`` is created to store the result
of this command.
If the full path to a file is found the result is stored in the variable
and the search will not be repeated unless the variable is cleared.
If nothing is found, the result will be
``<VAR>-NOTFOUND``, and the search will be attempted again the
next time find_file is invoked with the same variable.

Options include:

``NAMES``
  Specify one or more possible names for the full path to a file.

  When using this to specify names with and without a version
  suffix, we recommend specifying the unversioned name first
  so that locally-built packages can be found before those
  provided by distributions.

``HINTS``, ``PATHS``
  Specify directories to search in addition to the default locations.
  The ``ENV var`` sub-option reads paths from a system environment
  variable.

``PATH_SUFFIXES``
  Specify additional subdirectories to check below each directory
  location otherwise considered.

``DOC``
  Specify the documentation string for the ``<VAR>`` cache entry.

If ``NO_DEFAULT_PATH`` is specified, then no additional paths are
added to the search.
If ``NO_DEFAULT_PATH`` is not specified, the search process is as follows:

1. Search paths specified in cmake-specific cache variables.
   These are intended to be used on the command line with a ``-DVAR=value``.
   The values are interpreted as :ref:`;-lists <CMake Language Lists>`.
   This can be skipped if ``NO_CMAKE_PATH`` is passed.

   * ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_INCLUDE_PATH``
   * ``CMAKE_FRAMEWORK_PATH``

2. Search paths specified in cmake-specific environment variables.
   These are intended to be set in the user's shell configuration,
   and therefore use the host's native path separator
   (``;`` on Windows and ``:`` on UNIX).
   This can be skipped if ``NO_CMAKE_ENVIRONMENT_PATH`` is passed.

   * ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_INCLUDE_PATH``
   * ``CMAKE_FRAMEWORK_PATH``

3. Search the paths specified by the ``HINTS`` option.
   These should be paths computed by system introspection, such as a
   hint provided by the location of another item already found.
   Hard-coded guesses should be specified with the ``PATHS`` option.

4. Search the standard system environment variables.
   This can be skipped if ``NO_SYSTEM_ENVIRONMENT_PATH`` is an argument.

   * Directories in ``INCLUDE``. On Windows hosts: ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>/[s]bin`` in ``PATH``, and ``<entry>/include`` for other entries in ``PATH``, and the directories in ``PATH`` itself.

5. Search cmake variables defined in the Platform files
   for the current system.  This can be skipped if ``NO_CMAKE_SYSTEM_PATH``
   is passed.

   * ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>`` in ``CMAKE_SYSTEM_PREFIX_PATH``
   * ``CMAKE_SYSTEM_INCLUDE_PATH``
   * ``CMAKE_SYSTEM_FRAMEWORK_PATH``

6. Search the paths specified by the PATHS option
   or in the short-hand version of the command.
   These are typically hard-coded guesses.

On OS X the ``CMAKE_FIND_FRAMEWORK`` and
``CMAKE_FIND_APPBUNDLE`` variables determine the order of
preference between Apple-style and unix-style package components.

The CMake variable ``CMAKE_FIND_ROOT_PATH`` specifies one or more
directories to be prepended to all other search directories.  This
effectively "re-roots" the entire search under given locations.
Paths which are descendants of the ``CMAKE_STAGING_PREFIX`` are excluded
from this re-rooting, because that variable is always a path on the host system.
By default the ``CMAKE_FIND_ROOT_PATH`` is empty.

The ``CMAKE_SYSROOT`` variable can also be used to specify exactly one
directory to use as a prefix.  Setting ``CMAKE_SYSROOT`` also has other
effects.  See the documentation for that variable for more.

These variables are especially useful when cross-compiling to
point to the root directory of the target environment and CMake will
search there too.  By default at first the directories listed in
``CMAKE_FIND_ROOT_PATH`` are searched, then the ``CMAKE_SYSROOT``
directory is searched, and then the non-rooted directories will be
searched.  The default behavior can be adjusted by setting
``CMAKE_FIND_ROOT_PATH_MODE_INCLUDE``.  This behavior can be manually
overridden on a per-call basis using options:

``CMAKE_FIND_ROOT_PATH_BOTH``
  Search in the order described above.

``NO_CMAKE_FIND_ROOT_PATH``
  Do not use the ``CMAKE_FIND_ROOT_PATH`` variable.

``ONLY_CMAKE_FIND_ROOT_PATH``
  Search only the re-rooted directories and directories below
  ``CMAKE_STAGING_PREFIX``.

The default search order is designed to be most-specific to
least-specific for common use cases.
Projects may override the order by simply calling the command
multiple times and using the ``NO_*`` options:

 find_file (<VAR> NAMES name PATHS paths... NO_DEFAULT_PATH)
 find_file (<VAR> NAMES name)

Once one of the calls succeeds the result variable will be set
and stored in the cache so that no call will search again.

find_library
------------

A short-hand signature is:

 find_library (<VAR> name1 [path1 path2 ...])

The general signature is:

 find_library (
           <VAR>
           name | NAMES name1 [name2 ...] [NAMES_PER_DIR]
           [HINTS path1 [path2 ... ENV var]]
           [PATHS path1 [path2 ... ENV var]]
           [PATH_SUFFIXES suffix1 [suffix2 ...]]
           [DOC "cache documentation string"]
           [NO_DEFAULT_PATH]
           [NO_CMAKE_PATH]
           [NO_CMAKE_ENVIRONMENT_PATH]
           [NO_SYSTEM_ENVIRONMENT_PATH]
           [NO_CMAKE_SYSTEM_PATH]
           [CMAKE_FIND_ROOT_PATH_BOTH |
            ONLY_CMAKE_FIND_ROOT_PATH |
            NO_CMAKE_FIND_ROOT_PATH]
          )

This command is used to find a library.
A cache entry named by ``<VAR>`` is created to store the result
of this command.
If the library is found the result is stored in the variable
and the search will not be repeated unless the variable is cleared.
If nothing is found, the result will be
``<VAR>-NOTFOUND``, and the search will be attempted again the
next time find_library is invoked with the same variable.

Options include:

``NAMES``
  Specify one or more possible names for the library.

  When using this to specify names with and without a version
  suffix, we recommend specifying the unversioned name first
  so that locally-built packages can be found before those
  provided by distributions.

``HINTS``, ``PATHS``
  Specify directories to search in addition to the default locations.
  The ``ENV var`` sub-option reads paths from a system environment
  variable.

``PATH_SUFFIXES``
  Specify additional subdirectories to check below each directory
  location otherwise considered.

``DOC``
  Specify the documentation string for the ``<VAR>`` cache entry.

If ``NO_DEFAULT_PATH`` is specified, then no additional paths are
added to the search.
If ``NO_DEFAULT_PATH`` is not specified, the search process is as follows:

1. Search paths specified in cmake-specific cache variables.
   These are intended to be used on the command line with a ``-DVAR=value``.
   The values are interpreted as :ref:`;-lists <CMake Language Lists>`.
   This can be skipped if ``NO_CMAKE_PATH`` is passed.

   * ``<prefix>/lib/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/lib`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_LIBRARY_PATH``
   * ``CMAKE_FRAMEWORK_PATH``

2. Search paths specified in cmake-specific environment variables.
   These are intended to be set in the user's shell configuration,
   and therefore use the host's native path separator
   (``;`` on Windows and ``:`` on UNIX).
   This can be skipped if ``NO_CMAKE_ENVIRONMENT_PATH`` is passed.

   * ``<prefix>/lib/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/lib`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_LIBRARY_PATH``
   * ``CMAKE_FRAMEWORK_PATH``

3. Search the paths specified by the ``HINTS`` option.
   These should be paths computed by system introspection, such as a
   hint provided by the location of another item already found.
   Hard-coded guesses should be specified with the ``PATHS`` option.

4. Search the standard system environment variables.
   This can be skipped if ``NO_SYSTEM_ENVIRONMENT_PATH`` is an argument.

   * Directories in ``LIB``. On Windows hosts: ``<prefix>/lib/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/lib`` for each ``<prefix>/[s]bin`` in ``PATH``, and ``<entry>/lib`` for other entries in ``PATH``, and the directories in ``PATH`` itself.

5. Search cmake variables defined in the Platform files
   for the current system.  This can be skipped if ``NO_CMAKE_SYSTEM_PATH``
   is passed.

   * ``<prefix>/lib/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/lib`` for each ``<prefix>`` in ``CMAKE_SYSTEM_PREFIX_PATH``
   * ``CMAKE_SYSTEM_LIBRARY_PATH``
   * ``CMAKE_SYSTEM_FRAMEWORK_PATH``

6. Search the paths specified by the PATHS option
   or in the short-hand version of the command.
   These are typically hard-coded guesses.

On OS X the ``CMAKE_FIND_FRAMEWORK`` and
``CMAKE_FIND_APPBUNDLE`` variables determine the order of
preference between Apple-style and unix-style package components.

The CMake variable ``CMAKE_FIND_ROOT_PATH`` specifies one or more
directories to be prepended to all other search directories.  This
effectively "re-roots" the entire search under given locations.
Paths which are descendants of the ``CMAKE_STAGING_PREFIX`` are excluded
from this re-rooting, because that variable is always a path on the host system.
By default the ``CMAKE_FIND_ROOT_PATH`` is empty.

The ``CMAKE_SYSROOT`` variable can also be used to specify exactly one
directory to use as a prefix.  Setting ``CMAKE_SYSROOT`` also has other
effects.  See the documentation for that variable for more.

These variables are especially useful when cross-compiling to
point to the root directory of the target environment and CMake will
search there too.  By default at first the directories listed in
``CMAKE_FIND_ROOT_PATH`` are searched, then the ``CMAKE_SYSROOT``
directory is searched, and then the non-rooted directories will be
searched.  The default behavior can be adjusted by setting
``CMAKE_FIND_ROOT_PATH_MODE_LIBRARY``.  This behavior can be manually
overridden on a per-call basis using options:

``CMAKE_FIND_ROOT_PATH_BOTH``
  Search in the order described above.

``NO_CMAKE_FIND_ROOT_PATH``
  Do not use the ``CMAKE_FIND_ROOT_PATH`` variable.

``ONLY_CMAKE_FIND_ROOT_PATH``
  Search only the re-rooted directories and directories below
  ``CMAKE_STAGING_PREFIX``.

The default search order is designed to be most-specific to
least-specific for common use cases.
Projects may override the order by simply calling the command
multiple times and using the ``NO_*`` options:

 find_library (<VAR> NAMES name PATHS paths... NO_DEFAULT_PATH)
 find_library (<VAR> NAMES name)

Once one of the calls succeeds the result variable will be set
and stored in the cache so that no call will search again.

When more than one value is given to the ``NAMES`` option this command by
default will consider one name at a time and search every directory
for it.  The ``NAMES_PER_DIR`` option tells this command to consider one
directory at a time and search for all names in it.

Each library name given to the ``NAMES`` option is first considered
as a library file name and then considered with platform-specific
prefixes (e.g. ``lib``) and suffixes (e.g. ``.so``).  Therefore one
may specify library file names such as ``libfoo.a`` directly.
This can be used to locate static libraries on UNIX-like systems.

If the library found is a framework, then ``<VAR>`` will be set to the full
path to the framework ``<fullPath>/A.framework``.  When a full path to a
framework is used as a library, CMake will use a ``-framework A``, and a
``-F<fullPath>`` to link the framework to the target.

If the ``CMAKE_FIND_LIBRARY_CUSTOM_LIB_SUFFIX`` variable is set all
search paths will be tested as normal, with the suffix appended, and with
all matches of ``lib/`` replaced with
``lib${CMAKE_FIND_LIBRARY_CUSTOM_LIB_SUFFIX}/``.  This variable overrides
the ``FIND_LIBRARY_USE_LIB32_PATHS``,
``FIND_LIBRARY_USE_LIBX32_PATHS``,
and ``FIND_LIBRARY_USE_LIB64_PATHS`` global properties.

If the ``FIND_LIBRARY_USE_LIB32_PATHS`` global property is set
all search paths will be tested as normal, with ``32/`` appended, and
with all matches of ``lib/`` replaced with ``lib32/``.  This property is
automatically set for the platforms that are known to need it if at
least one of the languages supported by the ``project()`` command
is enabled.

If the ``FIND_LIBRARY_USE_LIBX32_PATHS`` global property is set
all search paths will be tested as normal, with ``x32/`` appended, and
with all matches of ``lib/`` replaced with ``libx32/``.  This property is
automatically set for the platforms that are known to need it if at
least one of the languages supported by the ``project()`` command
is enabled.

If the ``FIND_LIBRARY_USE_LIB64_PATHS`` global property is set
all search paths will be tested as normal, with ``64/`` appended, and
with all matches of ``lib/`` replaced with ``lib64/``.  This property is
automatically set for the platforms that are known to need it if at
least one of the languages supported by the ``project()`` command
is enabled.

find_package
------------

Load settings for an external project.

::

 find_package(<package> [version] [EXACT] [QUIET] [MODULE]
              [REQUIRED] [[COMPONENTS] [components...]]
              [OPTIONAL_COMPONENTS components...]
              [NO_POLICY_SCOPE])

Finds and loads settings from an external project.  ``<package>_FOUND``
will be set to indicate whether the package was found.  When the
package is found package-specific information is provided through
variables and :ref:`Imported Targets` documented by the package itself.  The
``QUIET`` option disables messages if the package cannot be found.  The
``MODULE`` option disables the second signature documented below.  The
``REQUIRED`` option stops processing with an error message if the package
cannot be found.

A package-specific list of required components may be listed after the
``COMPONENTS`` option (or after the ``REQUIRED`` option if present).
Additional optional components may be listed after
``OPTIONAL_COMPONENTS``.  Available components and their influence on
whether a package is considered to be found are defined by the target
package.

The ``[version]`` argument requests a version with which the package found
should be compatible (format is ``major[.minor[.patch[.tweak]]]``).  The
``EXACT`` option requests that the version be matched exactly.  If no
``[version]`` and/or component list is given to a recursive invocation
inside a find-module, the corresponding arguments are forwarded
automatically from the outer call (including the ``EXACT`` flag for
``[version]``).  Version support is currently provided only on a
package-by-package basis (details below).

User code should generally look for packages using the above simple
signature.  The remainder of this command documentation specifies the
full command signature and details of the search process.  Project
maintainers wishing to provide a package to be found by this command
are encouraged to read on.

The command has two modes by which it searches for packages: "Module"
mode and "Config" mode.  Module mode is available when the command is
invoked with the above reduced signature.  CMake searches for a file
called ``Find<package>.cmake`` in the ``CMAKE_MODULE_PATH``
followed by the CMake installation.  If the file is found, it is read
and processed by CMake.  It is responsible for finding the package,
checking the version, and producing any needed messages.  Many
find-modules provide limited or no support for versioning; check
the module documentation.  If no module is found and the ``MODULE``
option is not given the command proceeds to Config mode.

The complete Config mode command signature is::

 find_package(<package> [version] [EXACT] [QUIET]
              [REQUIRED] [[COMPONENTS] [components...]]
              [CONFIG|NO_MODULE]
              [NO_POLICY_SCOPE]
              [NAMES name1 [name2 ...]]
              [CONFIGS config1 [config2 ...]]
              [HINTS path1 [path2 ... ]]
              [PATHS path1 [path2 ... ]]
              [PATH_SUFFIXES suffix1 [suffix2 ...]]
              [NO_DEFAULT_PATH]
              [NO_CMAKE_PATH]
              [NO_CMAKE_ENVIRONMENT_PATH]
              [NO_SYSTEM_ENVIRONMENT_PATH]
              [NO_CMAKE_PACKAGE_REGISTRY]
              [NO_CMAKE_BUILDS_PATH] # Deprecated; does nothing.
              [NO_CMAKE_SYSTEM_PATH]
              [NO_CMAKE_SYSTEM_PACKAGE_REGISTRY]
              [CMAKE_FIND_ROOT_PATH_BOTH |
               ONLY_CMAKE_FIND_ROOT_PATH |
               NO_CMAKE_FIND_ROOT_PATH])

The ``CONFIG`` option may be used to skip Module mode explicitly and
switch to Config mode.  It is synonymous to using ``NO_MODULE``.  Config
mode is also implied by use of options not specified in the reduced
signature.

Config mode attempts to locate a configuration file provided by the
package to be found.  A cache entry called ``<package>_DIR`` is created to
hold the directory containing the file.  By default the command
searches for a package with the name ``<package>``.  If the ``NAMES`` option
is given the names following it are used instead of ``<package>``.  The
command searches for a file called ``<name>Config.cmake`` or
``<lower-case-name>-config.cmake`` for each name specified.  A
replacement set of possible configuration file names may be given
using the ``CONFIGS`` option.  The search procedure is specified below.
Once found, the configuration file is read and processed by CMake.
Since the file is provided by the package it already knows the
location of package contents.  The full path to the configuration file
is stored in the cmake variable ``<package>_CONFIG``.

All configuration files which have been considered by CMake while
searching for an installation of the package with an appropriate
version are stored in the cmake variable ``<package>_CONSIDERED_CONFIGS``,
the associated versions in ``<package>_CONSIDERED_VERSIONS``.

If the package configuration file cannot be found CMake will generate
an error describing the problem unless the ``QUIET`` argument is
specified.  If ``REQUIRED`` is specified and the package is not found a
fatal error is generated and the configure step stops executing.  If
``<package>_DIR`` has been set to a directory not containing a
configuration file CMake will ignore it and search from scratch.

When the ``[version]`` argument is given Config mode will only find a
version of the package that claims compatibility with the requested
version (format is ``major[.minor[.patch[.tweak]]]``).  If the ``EXACT``
option is given only a version of the package claiming an exact match
of the requested version may be found.  CMake does not establish any
convention for the meaning of version numbers.  Package version
numbers are checked by "version" files provided by the packages
themselves.  For a candidate package configuration file
``<config-file>.cmake`` the corresponding version file is located next
to it and named either ``<config-file>-version.cmake`` or
``<config-file>Version.cmake``.  If no such version file is available
then the configuration file is assumed to not be compatible with any
requested version.  A basic version file containing generic version
matching code can be created using the
``CMakePackageConfigHelpers`` module.  When a version file
is found it is loaded to check the requested version number.  The
version file is loaded in a nested scope in which the following
variables have been defined:

``PACKAGE_FIND_NAME``
  the ``<package>`` name
``PACKAGE_FIND_VERSION``
  full requested version string
``PACKAGE_FIND_VERSION_MAJOR``
  major version if requested, else 0
``PACKAGE_FIND_VERSION_MINOR``
  minor version if requested, else 0
``PACKAGE_FIND_VERSION_PATCH``
  patch version if requested, else 0
``PACKAGE_FIND_VERSION_TWEAK``
  tweak version if requested, else 0
``PACKAGE_FIND_VERSION_COUNT``
  number of version components, 0 to 4

The version file checks whether it satisfies the requested version and
sets these variables:

``PACKAGE_VERSION``
  full provided version string
``PACKAGE_VERSION_EXACT``
  true if version is exact match
``PACKAGE_VERSION_COMPATIBLE``
  true if version is compatible
``PACKAGE_VERSION_UNSUITABLE``
  true if unsuitable as any version

These variables are checked by the ``find_package`` command to determine
whether the configuration file provides an acceptable version.  They
are not available after the find_package call returns.  If the version
is acceptable the following variables are set:

``<package>_VERSION``
  full provided version string
``<package>_VERSION_MAJOR``
  major version if provided, else 0
``<package>_VERSION_MINOR``
  minor version if provided, else 0
``<package>_VERSION_PATCH``
  patch version if provided, else 0
``<package>_VERSION_TWEAK``
  tweak version if provided, else 0
``<package>_VERSION_COUNT``
  number of version components, 0 to 4

and the corresponding package configuration file is loaded.
When multiple package configuration files are available whose version files
claim compatibility with the version requested it is unspecified which
one is chosen: unless the variable ``CMAKE_FIND_PACKAGE_SORT_ORDER``
is set no attempt is made to choose a highest or closest version number.

To control the order in which ``find_package`` checks for compatibiliy use
the two variables ``CMAKE_FIND_PACKAGE_SORT_ORDER`` and
``CMAKE_FIND_PACKAGE_SORT_DIRECTION``.
For instance in order to select the highest version one can set::

 SET(CMAKE_FIND_PACKAGE_SORT_ORDER NATURAL)
 SET(CMAKE_FIND_PACKAGE_SORT_DIRECTION DEC)

before calling ``find_package``.

Config mode provides an elaborate interface and search procedure.
Much of the interface is provided for completeness and for use
internally by find-modules loaded by Module mode.  Most user code
should simply call::

 find_package(<package> [major[.minor]] [EXACT] [REQUIRED|QUIET])

in order to find a package.  Package maintainers providing CMake
package configuration files are encouraged to name and install them
such that the procedure outlined below will find them without
requiring use of additional options.

CMake constructs a set of possible installation prefixes for the
package.  Under each prefix several directories are searched for a
configuration file.  The tables below show the directories searched.
Each entry is meant for installation trees following Windows (W), UNIX
(U), or Apple (A) conventions::

 <prefix>/                                                       (W)
 <prefix>/(cmake|CMake)/                                         (W)
 <prefix>/<name>*/                                               (W)
 <prefix>/<name>*/(cmake|CMake)/                                 (W)
 <prefix>/(lib/<arch>|lib|share)/cmake/<name>*/                  (U)
 <prefix>/(lib/<arch>|lib|share)/<name>*/                        (U)
 <prefix>/(lib/<arch>|lib|share)/<name>*/(cmake|CMake)/          (U)
 <prefix>/<name>*/(lib/<arch>|lib|share)/cmake/<name>*/          (W/U)
 <prefix>/<name>*/(lib/<arch>|lib|share)/<name>*/                (W/U)
 <prefix>/<name>*/(lib/<arch>|lib|share)/<name>*/(cmake|CMake)/  (W/U)

On systems supporting OS X Frameworks and Application Bundles the
following directories are searched for frameworks or bundles
containing a configuration file::

 <prefix>/<name>.framework/Resources/                    (A)
 <prefix>/<name>.framework/Resources/CMake/              (A)
 <prefix>/<name>.framework/Versions/*/Resources/         (A)
 <prefix>/<name>.framework/Versions/*/Resources/CMake/   (A)
 <prefix>/<name>.app/Contents/Resources/                 (A)
 <prefix>/<name>.app/Contents/Resources/CMake/           (A)

In all cases the ``<name>`` is treated as case-insensitive and corresponds
to any of the names specified (``<package>`` or names given by ``NAMES``).
Paths with ``lib/<arch>`` are enabled if the
``CMAKE_LIBRARY_ARCHITECTURE`` variable is set.  If ``PATH_SUFFIXES``
is specified the suffixes are appended to each (W) or (U) directory entry
one-by-one.

This set of directories is intended to work in cooperation with
projects that provide configuration files in their installation trees.
Directories above marked with (W) are intended for installations on
Windows where the prefix may point at the top of an application's
installation directory.  Those marked with (U) are intended for
installations on UNIX platforms where the prefix is shared by multiple
packages.  This is merely a convention, so all (W) and (U) directories
are still searched on all platforms.  Directories marked with (A) are
intended for installations on Apple platforms.  The
``CMAKE_FIND_FRAMEWORK`` and ``CMAKE_FIND_APPBUNDLE``
variables determine the order of preference.

The set of installation prefixes is constructed using the following
steps.  If ``NO_DEFAULT_PATH`` is specified all ``NO_*`` options are
enabled.

1. Search paths specified in cmake-specific cache variables.  These
   are intended to be used on the command line with a ``-DVAR=value``.
   The values are interpreted as :ref:`;-lists <CMake Language Lists>`.
   This can be skipped if ``NO_CMAKE_PATH`` is passed::

 CMAKE_PREFIX_PATH
 CMAKE_FRAMEWORK_PATH
 CMAKE_APPBUNDLE_PATH

2. Search paths specified in cmake-specific environment variables.
   These are intended to be set in the user's shell configuration,
   and therefore use the host's native path separator
   (``;`` on Windows and ``:`` on UNIX).
   This can be skipped if ``NO_CMAKE_ENVIRONMENT_PATH`` is passed::

 <package>_DIR
 CMAKE_PREFIX_PATH
 CMAKE_FRAMEWORK_PATH
 CMAKE_APPBUNDLE_PATH

3. Search paths specified by the ``HINTS`` option.  These should be paths
   computed by system introspection, such as a hint provided by the
   location of another item already found.  Hard-coded guesses should
   be specified with the ``PATHS`` option.

4. Search the standard system environment variables.  This can be
   skipped if ``NO_SYSTEM_ENVIRONMENT_PATH`` is passed.  Path entries
   ending in ``/bin`` or ``/sbin`` are automatically converted to their
   parent directories::

 PATH

5. Search paths stored in the CMake :ref:`User Package Registry`.
   This can be skipped if ``NO_CMAKE_PACKAGE_REGISTRY`` is passed or by
   setting the ``CMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY``
   to ``TRUE``.
   See the ``cmake-packages(7)`` manual for details on the user
   package registry.

6. Search cmake variables defined in the Platform files for the
   current system.  This can be skipped if ``NO_CMAKE_SYSTEM_PATH`` is
   passed::

 CMAKE_SYSTEM_PREFIX_PATH
 CMAKE_SYSTEM_FRAMEWORK_PATH
 CMAKE_SYSTEM_APPBUNDLE_PATH

7. Search paths stored in the CMake :ref:`System Package Registry`.
   This can be skipped if ``NO_CMAKE_SYSTEM_PACKAGE_REGISTRY`` is passed
   or by setting the
   ``CMAKE_FIND_PACKAGE_NO_SYSTEM_PACKAGE_REGISTRY`` to ``TRUE``.
   See the ``cmake-packages(7)`` manual for details on the system
   package registry.

8. Search paths specified by the ``PATHS`` option.  These are typically
   hard-coded guesses.

The CMake variable ``CMAKE_FIND_ROOT_PATH`` specifies one or more
directories to be prepended to all other search directories.  This
effectively "re-roots" the entire search under given locations.
Paths which are descendants of the ``CMAKE_STAGING_PREFIX`` are excluded
from this re-rooting, because that variable is always a path on the host system.
By default the ``CMAKE_FIND_ROOT_PATH`` is empty.

The ``CMAKE_SYSROOT`` variable can also be used to specify exactly one
directory to use as a prefix.  Setting ``CMAKE_SYSROOT`` also has other
effects.  See the documentation for that variable for more.

These variables are especially useful when cross-compiling to
point to the root directory of the target environment and CMake will
search there too.  By default at first the directories listed in
``CMAKE_FIND_ROOT_PATH`` are searched, then the ``CMAKE_SYSROOT``
directory is searched, and then the non-rooted directories will be
searched.  The default behavior can be adjusted by setting
``CMAKE_FIND_ROOT_PATH_MODE_PACKAGE``.  This behavior can be manually
overridden on a per-call basis using options:

``CMAKE_FIND_ROOT_PATH_BOTH``
  Search in the order described above.

``NO_CMAKE_FIND_ROOT_PATH``
  Do not use the ``CMAKE_FIND_ROOT_PATH`` variable.

``ONLY_CMAKE_FIND_ROOT_PATH``
  Search only the re-rooted directories and directories below
  ``CMAKE_STAGING_PREFIX``.

The default search order is designed to be most-specific to
least-specific for common use cases.
Projects may override the order by simply calling the command
multiple times and using the ``NO_*`` options:

 find_package (<package> PATHS paths... NO_DEFAULT_PATH)
 find_package (<package>)

Once one of the calls succeeds the result variable will be set
and stored in the cache so that no call will search again.

Every non-REQUIRED ``find_package`` call can be disabled by setting the
``CMAKE_DISABLE_FIND_PACKAGE_<PackageName>`` variable to ``TRUE``.

When loading a find module or package configuration file ``find_package``
defines variables to provide information about the call arguments (and
restores their original state before returning):

``CMAKE_FIND_PACKAGE_NAME``
  the ``<package>`` name which is searched for
``<package>_FIND_REQUIRED``
  true if ``REQUIRED`` option was given
``<package>_FIND_QUIETLY``
  true if ``QUIET`` option was given
``<package>_FIND_VERSION``
  full requested version string
``<package>_FIND_VERSION_MAJOR``
  major version if requested, else 0
``<package>_FIND_VERSION_MINOR``
  minor version if requested, else 0
``<package>_FIND_VERSION_PATCH``
  patch version if requested, else 0
``<package>_FIND_VERSION_TWEAK``
  tweak version if requested, else 0
``<package>_FIND_VERSION_COUNT``
  number of version components, 0 to 4
``<package>_FIND_VERSION_EXACT``
  true if ``EXACT`` option was given
``<package>_FIND_COMPONENTS``
  list of requested components
``<package>_FIND_REQUIRED_<c>``
  true if component ``<c>`` is required,
  false if component ``<c>`` is optional

In Module mode the loaded find module is responsible to honor the
request detailed by these variables; see the find module for details.
In Config mode ``find_package`` handles ``REQUIRED``, ``QUIET``, and
``[version]`` options automatically but leaves it to the package
configuration file to handle components in a way that makes sense
for the package.  The package configuration file may set
``<package>_FOUND`` to false to tell ``find_package`` that component
requirements are not satisfied.

See the ``cmake_policy()`` command documentation for discussion
of the ``NO_POLICY_SCOPE`` option.

find_path
---------

A short-hand signature is:

 find_path (<VAR> name1 [path1 path2 ...])

The general signature is:

 find_path (
           <VAR>
           name | NAMES name1 [name2 ...]
           [HINTS path1 [path2 ... ENV var]]
           [PATHS path1 [path2 ... ENV var]]
           [PATH_SUFFIXES suffix1 [suffix2 ...]]
           [DOC "cache documentation string"]
           [NO_DEFAULT_PATH]
           [NO_CMAKE_PATH]
           [NO_CMAKE_ENVIRONMENT_PATH]
           [NO_SYSTEM_ENVIRONMENT_PATH]
           [NO_CMAKE_SYSTEM_PATH]
           [CMAKE_FIND_ROOT_PATH_BOTH |
            ONLY_CMAKE_FIND_ROOT_PATH |
            NO_CMAKE_FIND_ROOT_PATH]
          )

This command is used to find a directory containing the named file.
A cache entry named by ``<VAR>`` is created to store the result
of this command.
If the file in a directory is found the result is stored in the variable
and the search will not be repeated unless the variable is cleared.
If nothing is found, the result will be
``<VAR>-NOTFOUND``, and the search will be attempted again the
next time find_path is invoked with the same variable.

Options include:

``NAMES``
  Specify one or more possible names for the file in a directory.

  When using this to specify names with and without a version
  suffix, we recommend specifying the unversioned name first
  so that locally-built packages can be found before those
  provided by distributions.

``HINTS``, ``PATHS``
  Specify directories to search in addition to the default locations.
  The ``ENV var`` sub-option reads paths from a system environment
  variable.

``PATH_SUFFIXES``
  Specify additional subdirectories to check below each directory
  location otherwise considered.

``DOC``
  Specify the documentation string for the ``<VAR>`` cache entry.

If ``NO_DEFAULT_PATH`` is specified, then no additional paths are
added to the search.
If ``NO_DEFAULT_PATH`` is not specified, the search process is as follows:

1. Search paths specified in cmake-specific cache variables.
   These are intended to be used on the command line with a ``-DVAR=value``.
   The values are interpreted as :ref:`;-lists <CMake Language Lists>`.
   This can be skipped if ``NO_CMAKE_PATH`` is passed.

   * ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_INCLUDE_PATH``
   * ``CMAKE_FRAMEWORK_PATH``

2. Search paths specified in cmake-specific environment variables.
   These are intended to be set in the user's shell configuration,
   and therefore use the host's native path separator
   (``;`` on Windows and ``:`` on UNIX).
   This can be skipped if ``NO_CMAKE_ENVIRONMENT_PATH`` is passed.

   * ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_INCLUDE_PATH``
   * ``CMAKE_FRAMEWORK_PATH``

3. Search the paths specified by the ``HINTS`` option.
   These should be paths computed by system introspection, such as a
   hint provided by the location of another item already found.
   Hard-coded guesses should be specified with the ``PATHS`` option.

4. Search the standard system environment variables.
   This can be skipped if ``NO_SYSTEM_ENVIRONMENT_PATH`` is an argument.

   * Directories in ``INCLUDE``. On Windows hosts: ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>/[s]bin`` in ``PATH``, and ``<entry>/include`` for other entries in ``PATH``, and the directories in ``PATH`` itself.

5. Search cmake variables defined in the Platform files
   for the current system.  This can be skipped if ``NO_CMAKE_SYSTEM_PATH``
   is passed.

   * ``<prefix>/include/<arch>`` if ``CMAKE_LIBRARY_ARCHITECTURE`` is set, and ``<prefix>/include`` for each ``<prefix>`` in ``CMAKE_SYSTEM_PREFIX_PATH``
   * ``CMAKE_SYSTEM_INCLUDE_PATH``
   * ``CMAKE_SYSTEM_FRAMEWORK_PATH``

6. Search the paths specified by the PATHS option
   or in the short-hand version of the command.
   These are typically hard-coded guesses.

On OS X the ``CMAKE_FIND_FRAMEWORK`` and
``CMAKE_FIND_APPBUNDLE`` variables determine the order of
preference between Apple-style and unix-style package components.

The CMake variable ``CMAKE_FIND_ROOT_PATH`` specifies one or more
directories to be prepended to all other search directories.  This
effectively "re-roots" the entire search under given locations.
Paths which are descendants of the ``CMAKE_STAGING_PREFIX`` are excluded
from this re-rooting, because that variable is always a path on the host system.
By default the ``CMAKE_FIND_ROOT_PATH`` is empty.

The ``CMAKE_SYSROOT`` variable can also be used to specify exactly one
directory to use as a prefix.  Setting ``CMAKE_SYSROOT`` also has other
effects.  See the documentation for that variable for more.

These variables are especially useful when cross-compiling to
point to the root directory of the target environment and CMake will
search there too.  By default at first the directories listed in
``CMAKE_FIND_ROOT_PATH`` are searched, then the ``CMAKE_SYSROOT``
directory is searched, and then the non-rooted directories will be
searched.  The default behavior can be adjusted by setting
``CMAKE_FIND_ROOT_PATH_MODE_INCLUDE``.  This behavior can be manually
overridden on a per-call basis using options:

``CMAKE_FIND_ROOT_PATH_BOTH``
  Search in the order described above.

``NO_CMAKE_FIND_ROOT_PATH``
  Do not use the ``CMAKE_FIND_ROOT_PATH`` variable.

``ONLY_CMAKE_FIND_ROOT_PATH``
  Search only the re-rooted directories and directories below
  ``CMAKE_STAGING_PREFIX``.

The default search order is designed to be most-specific to
least-specific for common use cases.
Projects may override the order by simply calling the command
multiple times and using the ``NO_*`` options:

 find_path (<VAR> NAMES name PATHS paths... NO_DEFAULT_PATH)
 find_path (<VAR> NAMES name)

Once one of the calls succeeds the result variable will be set
and stored in the cache so that no call will search again.

When searching for frameworks, if the file is specified as ``A/b.h``, then
the framework search will look for ``A.framework/Headers/b.h``.  If that
is found the path will be set to the path to the framework.  CMake
will convert this to the correct ``-F`` option to include the file.

find_program
------------

A short-hand signature is:

 find_program (<VAR> name1 [path1 path2 ...])

The general signature is:

 find_program (
           <VAR>
           name | NAMES name1 [name2 ...] [NAMES_PER_DIR]
           [HINTS path1 [path2 ... ENV var]]
           [PATHS path1 [path2 ... ENV var]]
           [PATH_SUFFIXES suffix1 [suffix2 ...]]
           [DOC "cache documentation string"]
           [NO_DEFAULT_PATH]
           [NO_CMAKE_PATH]
           [NO_CMAKE_ENVIRONMENT_PATH]
           [NO_SYSTEM_ENVIRONMENT_PATH]
           [NO_CMAKE_SYSTEM_PATH]
           [CMAKE_FIND_ROOT_PATH_BOTH |
            ONLY_CMAKE_FIND_ROOT_PATH |
            NO_CMAKE_FIND_ROOT_PATH]
          )

This command is used to find a program.
A cache entry named by ``<VAR>`` is created to store the result
of this command.
If the program is found the result is stored in the variable
and the search will not be repeated unless the variable is cleared.
If nothing is found, the result will be
``<VAR>-NOTFOUND``, and the search will be attempted again the
next time find_program is invoked with the same variable.

Options include:

``NAMES``
  Specify one or more possible names for the program.

  When using this to specify names with and without a version
  suffix, we recommend specifying the unversioned name first
  so that locally-built packages can be found before those
  provided by distributions.

``HINTS``, ``PATHS``
  Specify directories to search in addition to the default locations.
  The ``ENV var`` sub-option reads paths from a system environment
  variable.

``PATH_SUFFIXES``
  Specify additional subdirectories to check below each directory
  location otherwise considered.

``DOC``
  Specify the documentation string for the ``<VAR>`` cache entry.

If ``NO_DEFAULT_PATH`` is specified, then no additional paths are
added to the search.
If ``NO_DEFAULT_PATH`` is not specified, the search process is as follows:

1. Search paths specified in cmake-specific cache variables.
   These are intended to be used on the command line with a ``-DVAR=value``.
   The values are interpreted as :ref:`;-lists <CMake Language Lists>`.
   This can be skipped if ``NO_CMAKE_PATH`` is passed.

   * ``<prefix>/[s]bin`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_PROGRAM_PATH``
   * ``CMAKE_APPBUNDLE_PATH``

2. Search paths specified in cmake-specific environment variables.
   These are intended to be set in the user's shell configuration,
   and therefore use the host's native path separator
   (``;`` on Windows and ``:`` on UNIX).
   This can be skipped if ``NO_CMAKE_ENVIRONMENT_PATH`` is passed.

   * ``<prefix>/[s]bin`` for each ``<prefix>`` in ``CMAKE_PREFIX_PATH``
   * ``CMAKE_PROGRAM_PATH``
   * ``CMAKE_APPBUNDLE_PATH``

3. Search the paths specified by the ``HINTS`` option.
   These should be paths computed by system introspection, such as a
   hint provided by the location of another item already found.
   Hard-coded guesses should be specified with the ``PATHS`` option.

4. Search the standard system environment variables.
   This can be skipped if ``NO_SYSTEM_ENVIRONMENT_PATH`` is an argument.

   * ``PATH``

5. Search cmake variables defined in the Platform files
   for the current system.  This can be skipped if ``NO_CMAKE_SYSTEM_PATH``
   is passed.

   * ``<prefix>/[s]bin`` for each ``<prefix>`` in ``CMAKE_SYSTEM_PREFIX_PATH``
   * ``CMAKE_SYSTEM_PROGRAM_PATH``
   * ``CMAKE_SYSTEM_APPBUNDLE_PATH``

6. Search the paths specified by the PATHS option
   or in the short-hand version of the command.
   These are typically hard-coded guesses.

On OS X the ``CMAKE_FIND_FRAMEWORK`` and
``CMAKE_FIND_APPBUNDLE`` variables determine the order of
preference between Apple-style and unix-style package components.

The CMake variable ``CMAKE_FIND_ROOT_PATH`` specifies one or more
directories to be prepended to all other search directories.  This
effectively "re-roots" the entire search under given locations.
Paths which are descendants of the ``CMAKE_STAGING_PREFIX`` are excluded
from this re-rooting, because that variable is always a path on the host system.
By default the ``CMAKE_FIND_ROOT_PATH`` is empty.

The ``CMAKE_SYSROOT`` variable can also be used to specify exactly one
directory to use as a prefix.  Setting ``CMAKE_SYSROOT`` also has other
effects.  See the documentation for that variable for more.

These variables are especially useful when cross-compiling to
point to the root directory of the target environment and CMake will
search there too.  By default at first the directories listed in
``CMAKE_FIND_ROOT_PATH`` are searched, then the ``CMAKE_SYSROOT``
directory is searched, and then the non-rooted directories will be
searched.  The default behavior can be adjusted by setting
``CMAKE_FIND_ROOT_PATH_MODE_PROGRAM``.  This behavior can be manually
overridden on a per-call basis using options:

``CMAKE_FIND_ROOT_PATH_BOTH``
  Search in the order described above.

``NO_CMAKE_FIND_ROOT_PATH``
  Do not use the ``CMAKE_FIND_ROOT_PATH`` variable.

``ONLY_CMAKE_FIND_ROOT_PATH``
  Search only the re-rooted directories and directories below
  ``CMAKE_STAGING_PREFIX``.

The default search order is designed to be most-specific to
least-specific for common use cases.
Projects may override the order by simply calling the command
multiple times and using the ``NO_*`` options:

 find_program (<VAR> NAMES name PATHS paths... NO_DEFAULT_PATH)
 find_program (<VAR> NAMES name)

Once one of the calls succeeds the result variable will be set
and stored in the cache so that no call will search again.

When more than one value is given to the ``NAMES`` option this command by
default will consider one name at a time and search every directory
for it.  The ``NAMES_PER_DIR`` option tells this command to consider one
directory at a time and search for all names in it.

foreach
-------

Evaluate a group of commands for each value in a list.

::

 foreach(loop_var arg1 arg2 ...)
   COMMAND1(ARGS ...)
   COMMAND2(ARGS ...)
   ...
 endforeach(loop_var)

All commands between foreach and the matching endforeach are recorded
without being invoked.  Once the endforeach is evaluated, the recorded
list of commands is invoked once for each argument listed in the
original foreach command.  Before each iteration of the loop
``${loop_var}`` will be set as a variable with the current value in the
list.

::

 foreach(loop_var RANGE total)
 foreach(loop_var RANGE start stop [step])

Foreach can also iterate over a generated range of numbers.  There are
three types of this iteration:

* When specifying single number, the range will have elements 0 to
  "total".

* When specifying two numbers, the range will have elements from the
  first number to the second number.

* The third optional number is the increment used to iterate from the
  first number to the second number.

::

 foreach(loop_var IN [LISTS [list1 [...]]]
                     [ITEMS [item1 [...]]])

Iterates over a precise list of items.  The ``LISTS`` option names
list-valued variables to be traversed, including empty elements (an
empty string is a zero-length list).  (Note macro
arguments are not variables.)  The ``ITEMS`` option ends argument
parsing and includes all arguments following it in the iteration.

function
--------

Start recording a function for later invocation as a command::

 function(<name> [arg1 [arg2 [arg3 ...]]])
   COMMAND1(ARGS ...)
   COMMAND2(ARGS ...)
   ...
 endfunction(<name>)

Define a function named ``<name>`` that takes arguments named ``arg1``,
``arg2``, ``arg3``, (...).
Commands listed after function, but before the matching
``endfunction()``, are not invoked until the function is invoked.
When it is invoked, the commands recorded in the function are first
modified by replacing formal parameters (``${arg1}``) with the arguments
passed, and then invoked as normal commands.
In addition to referencing the formal parameters you can reference the
``ARGC`` variable which will be set to the number of arguments passed
into the function as well as ``ARGV0``, ``ARGV1``, ``ARGV2``, ...  which
will have the actual values of the arguments passed in.
This facilitates creating functions with optional arguments.
Additionally ``ARGV`` holds the list of all arguments given to the
function and ``ARGN`` holds the list of arguments past the last expected
argument.
Referencing to ``ARGV#`` arguments beyond ``ARGC`` have undefined
behavior. Checking that ``ARGC`` is greater than ``#`` is the only way
to ensure that ``ARGV#`` was passed to the function as an extra
argument.

A function opens a new scope: see ``set(var PARENT_SCOPE)`` for
details.

See the ``cmake_policy()`` command documentation for the behavior
of policies inside functions.

get_cmake_property
------------------

Get a global property of the CMake instance.

::

 get_cmake_property(VAR property)

Get a global property from the CMake instance.  The value of the property is
stored in the variable ``VAR``.  If the property is not found, ``VAR``
will be  set to "NOTFOUND".  See the ``cmake-properties(7)`` manual
for available properties.

See also the ``get_property()`` command ``GLOBAL`` option.

In addition to global properties, this command (for historical reasons)
also supports the ``VARIABLES`` and ``MACROS`` directory
properties.  It also supports a special ``COMPONENTS`` global property that
lists the components given to the ``install()`` command.

get_directory_property
----------------------

Get a property of ``DIRECTORY`` scope.

::

 get_directory_property(<variable> [DIRECTORY <dir>] <prop-name>)

Store a property of directory scope in the named variable.  If the
property is not defined the empty-string is returned.  The ``DIRECTORY``
argument specifies another directory from which to retrieve the
property value.  The specified directory must have already been
traversed by CMake.

::

 get_directory_property(<variable> [DIRECTORY <dir>]
                        DEFINITION <var-name>)

Get a variable definition from a directory.  This form is useful to
get a variable definition from another directory.

See also the more general ``get_property()`` command.

get_filename_component
----------------------

Get a specific component of a full filename.

------------------------------------------------------------------------------

::

 get_filename_component(<VAR> <FileName> <COMP> [CACHE])

Set ``<VAR>`` to a component of ``<FileName>``, where ``<COMP>`` is one of:

::

 DIRECTORY = Directory without file name
 NAME      = File name without directory
 EXT       = File name longest extension (.b.c from d/a.b.c)
 NAME_WE   = File name without directory or longest extension
 PATH      = Legacy alias for DIRECTORY (use for CMake <= 2.8.11)

Paths are returned with forward slashes and have no trailing slashes.
The longest file extension is always considered.  If the optional
``CACHE`` argument is specified, the result variable is added to the
cache.

------------------------------------------------------------------------------

::

 get_filename_component(<VAR> <FileName>
                        <COMP> [BASE_DIR <BASE_DIR>]
                        [CACHE])

Set ``<VAR>`` to the absolute path of ``<FileName>``, where ``<COMP>`` is one
of:

::

 ABSOLUTE  = Full path to file
 REALPATH  = Full path to existing file with symlinks resolved

If the provided ``<FileName>`` is a relative path, it is evaluated relative
to the given base directory ``<BASE_DIR>``.  If no base directory is
provided, the default base directory will be
``CMAKE_CURRENT_SOURCE_DIR``.

Paths are returned with forward slashes and have no trailing slahes.  If the
optional ``CACHE`` argument is specified, the result variable is added to the
cache.

------------------------------------------------------------------------------

::

 get_filename_component(<VAR> <FileName>
                        PROGRAM [PROGRAM_ARGS <ARG_VAR>]
                        [CACHE])

The program in ``<FileName>`` will be found in the system search path or
left as a full path.  If ``PROGRAM_ARGS`` is present with ``PROGRAM``, then
any command-line arguments present in the ``<FileName>`` string are split
from the program name and stored in ``<ARG_VAR>``.  This is used to
separate a program name from its arguments in a command line string.

get_property
------------

Get a property.

::

 get_property(<variable>
              <GLOBAL             |
               DIRECTORY [dir]    |
               TARGET    <target> |
               SOURCE    <source> |
               INSTALL   <file>   |
               TEST      <test>   |
               CACHE     <entry>  |
               VARIABLE>
              PROPERTY <name>
              [SET | DEFINED | BRIEF_DOCS | FULL_DOCS])

Get one property from one object in a scope.  The first argument
specifies the variable in which to store the result.  The second
argument determines the scope from which to get the property.  It must
be one of the following:

``GLOBAL``
  Scope is unique and does not accept a name.

``DIRECTORY``
  Scope defaults to the current directory but another
  directory (already processed by CMake) may be named by full or
  relative path.

``TARGET``
  Scope must name one existing target.

``SOURCE``
  Scope must name one source file.

``INSTALL``
  Scope must name one installed file path.

``TEST``
  Scope must name one existing test.

``CACHE``
  Scope must name one cache entry.

``VARIABLE``
  Scope is unique and does not accept a name.

The required ``PROPERTY`` option is immediately followed by the name of
the property to get.  If the property is not set an empty value is
returned.  If the ``SET`` option is given the variable is set to a boolean
value indicating whether the property has been set.  If the ``DEFINED``
option is given the variable is set to a boolean value indicating
whether the property has been defined such as with the
``define_property()`` command.
If ``BRIEF_DOCS`` or ``FULL_DOCS`` is given then the variable is set to a
string containing documentation for the requested property.  If
documentation is requested for a property that has not been defined
``NOTFOUND`` is returned.

if
--

Conditionally execute a group of commands.

 if(expression)
   # then section.
   COMMAND1(ARGS ...)
   COMMAND2(ARGS ...)
   #...
 elseif(expression2)
   # elseif section.
   COMMAND1(ARGS ...)
   COMMAND2(ARGS ...)
   #...
 else(expression)
   # else section.
   COMMAND1(ARGS ...)
   COMMAND2(ARGS ...)
   #...
 endif(expression)

Evaluates the given expression.  If the result is true, the commands
in the THEN section are invoked.  Otherwise, the commands in the else
section are invoked.  The elseif and else sections are optional.  You
may have multiple elseif clauses.  Note that the expression in the
else and endif clause is optional.  Long expressions can be used and
there is a traditional order of precedence.  Parenthetical expressions
are evaluated first followed by unary tests such as ``EXISTS``,
``COMMAND``, and ``DEFINED``.  Then any binary tests such as
``EQUAL``, ``LESS``, ``LESS_EQUAL, ``GREATER``, ``GREATER_EQUAL``,
``STREQUAL``, ``STRLESS``, ``STRLESS_EQUAL``, ``STRGREATER``,
``STRGREATER_EQUAL``, ``VERSION_EQUAL``, ``VERSION_LESS``,
``VERSION_LESS_EQUAL``, ``VERSION_GREATER``, ``VERSION_GREATER_EQUAL``,
and ``MATCHES`` will be evaluated.  Then boolean ``NOT`` operators and
finally boolean ``AND`` and then ``OR`` operators will be evaluated.

Possible expressions are:

``if(<constant>)``
 True if the constant is ``1``, ``ON``, ``YES``, ``TRUE``, ``Y``,
 or a non-zero number.  False if the constant is ``0``, ``OFF``,
 ``NO``, ``FALSE``, ``N``, ``IGNORE``, ``NOTFOUND``, the empty string,
 or ends in the suffix ``-NOTFOUND``.  Named boolean constants are
 case-insensitive.  If the argument is not one of these specific
 constants, it is treated as a variable or string and the following
 signature is used.

``if(<variable|string>)``
 True if given a variable that is defined to a value that is not a false
 constant.  False otherwise.  (Note macro arguments are not variables.)

``if(NOT <expression>)``
 True if the expression is not true.

``if(<expr1> AND <expr2>)``
 True if both expressions would be considered true individually.

``if(<expr1> OR <expr2>)``
 True if either expression would be considered true individually.

``if(COMMAND command-name)``
 True if the given name is a command, macro or function that can be
 invoked.

``if(POLICY policy-id)``
 True if the given name is an existing policy (of the form ``CMP<NNNN>``).

``if(TARGET target-name)``
 True if the given name is an existing logical target name created
 by a call to the ``add_executable()``, ``add_library()``,
 or ``add_custom_target()`` command that has already been invoked
 (in any directory).

``if(TEST test-name)``
 True if the given name is an existing test name created by the
 ``add_test()`` command.

``if(EXISTS path-to-file-or-directory)``
 True if the named file or directory exists.  Behavior is well-defined
 only for full paths.

``if(file1 IS_NEWER_THAN file2)``
 True if ``file1`` is newer than ``file2`` or if one of the two files doesn't
 exist.  Behavior is well-defined only for full paths.  If the file
 time stamps are exactly the same, an ``IS_NEWER_THAN`` comparison returns
 true, so that any dependent build operations will occur in the event
 of a tie.  This includes the case of passing the same file name for
 both file1 and file2.

``if(IS_DIRECTORY path-to-directory)``
 True if the given name is a directory.  Behavior is well-defined only
 for full paths.

``if(IS_SYMLINK file-name)``
 True if the given name is a symbolic link.  Behavior is well-defined
 only for full paths.

``if(IS_ABSOLUTE path)``
 True if the given path is an absolute path.

``if(<variable|string> MATCHES regex)``
 True if the given string or variable's value matches the given regular
 expression.  See :ref:`Regex Specification` for regex format.
 ``()`` groups are captured in ``CMAKE_MATCH_<n>`` variables.

``if(<variable|string> LESS <variable|string>)``
 True if the given string or variable's value is a valid number and less
 than that on the right.

``if(<variable|string> GREATER <variable|string>)``
 True if the given string or variable's value is a valid number and greater
 than that on the right.

``if(<variable|string> EQUAL <variable|string>)``
 True if the given string or variable's value is a valid number and equal
 to that on the right.

``if(<variable|string> LESS_EQUAL <variable|string>)``
 True if the given string or variable's value is a valid number and less
 than or equal to that on the right.

``if(<variable|string> GREATER_EQUAL <variable|string>)``
 True if the given string or variable's value is a valid number and greater
 than or equal to that on the right.

``if(<variable|string> STRLESS <variable|string>)``
 True if the given string or variable's value is lexicographically less
 than the string or variable on the right.

``if(<variable|string> STRGREATER <variable|string>)``
 True if the given string or variable's value is lexicographically greater
 than the string or variable on the right.

``if(<variable|string> STREQUAL <variable|string>)``
 True if the given string or variable's value is lexicographically equal
 to the string or variable on the right.

``if(<variable|string> STRLESS_EQUAL <variable|string>)``
 True if the given string or variable's value is lexicographically less
 than or equal to the string or variable on the right.

``if(<variable|string> STRGREATER_EQUAL <variable|string>)``
 True if the given string or variable's value is lexicographically greater
 than or equal to the string or variable on the right.

``if(<variable|string> VERSION_LESS <variable|string>)``
 Component-wise integer version number comparison (version format is
 ``major[.minor[.patch[.tweak]]]``).

``if(<variable|string> VERSION_GREATER <variable|string>)``
 Component-wise integer version number comparison (version format is
 ``major[.minor[.patch[.tweak]]]``).

``if(<variable|string> VERSION_EQUAL <variable|string>)``
 Component-wise integer version number comparison (version format is
 ``major[.minor[.patch[.tweak]]]``).

``if(<variable|string> VERSION_LESS_EQUAL <variable|string>)``
 Component-wise integer version number comparison (version format is
 ``major[.minor[.patch[.tweak]]]``).

``if(<variable|string> VERSION_GREATER_EQUAL <variable|string>)``
 Component-wise integer version number comparison (version format is
 ``major[.minor[.patch[.tweak]]]``).

``if(<variable|string> IN_LIST <variable>)``
 True if the given element is contained in the named list variable.

``if(DEFINED <variable>)``
 True if the given variable is defined.  It does not matter if the
 variable is true or false just if it has been set.  (Note macro
 arguments are not variables.)

``if((expression) AND (expression OR (expression)))``
 The expressions inside the parenthesis are evaluated first and then
 the remaining expression is evaluated as in the previous examples.
 Where there are nested parenthesis the innermost are evaluated as part
 of evaluating the expression that contains them.

The if command was written very early in CMake's history, predating
the ``${}`` variable evaluation syntax, and for convenience evaluates
variables named by its arguments as shown in the above signatures.
Note that normal variable evaluation with ``${}`` applies before the if
command even receives the arguments.  Therefore code like::

 set(var1 OFF)
 set(var2 "var1")
 if(${var2})

appears to the if command as::

 if(var1)

and is evaluated according to the ``if(<variable>)`` case documented
above.  The result is ``OFF`` which is false.  However, if we remove the
``${}`` from the example then the command sees::

 if(var2)

which is true because ``var2`` is defined to "var1" which is not a false
constant.

Automatic evaluation applies in the other cases whenever the
above-documented signature accepts ``<variable|string>``:

* The left hand argument to ``MATCHES`` is first checked to see if it is
  a defined variable, if so the variable's value is used, otherwise the
  original value is used.

* If the left hand argument to ``MATCHES`` is missing it returns false
  without error

* Both left and right hand arguments to ``LESS``, ``GREATER``, ``EQUAL``,
  ``LESS_EQUAL``, and ``GREATER_EQUAL``, are independently tested to see if
  they are defined variables, if so their defined values are used otherwise
  the original value is used.

* Both left and right hand arguments to ``STRLESS``, ``STRGREATER``,
  ``STREQUAL``, ``STRLESS_EQUAL``, and ``STRGREATER_EQUAL`` are independently
  tested to see if they are defined variables, if so their defined values are
  used otherwise the original value is used.

* Both left and right hand arguments to ``VERSION_LESS``,
  ``VERSION_GREATER``, ``VERSION_EQUAL``, ``VERSION_LESS_EQUAL``, and
  ``VERSION_GREATER_EQUAL`` are independently tested to see if they are defined
  variables, if so their defined values are used otherwise the original value
  is used.

* The right hand argument to ``NOT`` is tested to see if it is a boolean
  constant, if so the value is used, otherwise it is assumed to be a
  variable and it is dereferenced.

* The left and right hand arguments to ``AND`` and ``OR`` are independently
  tested to see if they are boolean constants, if so they are used as
  such, otherwise they are assumed to be variables and are dereferenced.

To prevent ambiguity, potential variable or keyword names can be
specified in a :ref:`Quoted Argument` or a :ref:`Bracket Argument`.
A quoted or bracketed variable or keyword will be interpreted as a
string and not dereferenced or interpreted.
See policy ``CMP0054``.

include
-------

Load and run CMake code from a file or module.

::

 include(<file|module> [OPTIONAL] [RESULT_VARIABLE <VAR>]
                       [NO_POLICY_SCOPE])

Load and run CMake code from the file given.  Variable reads and
writes access the scope of the caller (dynamic scoping).  If ``OPTIONAL``
is present, then no error is raised if the file does not exist.  If
``RESULT_VARIABLE`` is given the variable will be set to the full filename
which has been included or NOTFOUND if it failed.

If a module is specified instead of a file, the file with name
``<modulename>.cmake`` is searched first in ``CMAKE_MODULE_PATH``,
then in the CMake module directory.  There is one exception to this: if
the file which calls ``include()`` is located itself in the CMake builtin
module directory, then first the CMake builtin module directory is searched and
``CMAKE_MODULE_PATH`` afterwards.  See also policy ``CMP0017``.

See the ``cmake_policy()`` command documentation for discussion of the
``NO_POLICY_SCOPE`` option.

list
----

List operations.

::

 list(LENGTH <list> <output variable>)
 list(GET <list> <element index> [<element index> ...]
      <output variable>)
 list(APPEND <list> [<element> ...])
 list(FILTER <list> <INCLUDE|EXCLUDE> REGEX <regular_expression>)
 list(FIND <list> <value> <output variable>)
 list(INSERT <list> <element_index> <element> [<element> ...])
 list(REMOVE_ITEM <list> <value> [<value> ...])
 list(REMOVE_AT <list> <index> [<index> ...])
 list(REMOVE_DUPLICATES <list>)
 list(REVERSE <list>)
 list(SORT <list>)

``LENGTH`` will return a given list's length.

``GET`` will return list of elements specified by indices from the list.

``APPEND`` will append elements to the list.

``FILTER`` will include or remove items from the list that match the
mode's pattern.
In ``REGEX`` mode, items will be matched against the given regular expression.
For more information on regular expressions see also the ``string()``
command.

``FIND`` will return the index of the element specified in the list or -1
if it wasn't found.

``INSERT`` will insert elements to the list to the specified location.

``REMOVE_AT`` and ``REMOVE_ITEM`` will remove items from the list.  The
difference is that ``REMOVE_ITEM`` will remove the given items, while
``REMOVE_AT`` will remove the items at the given indices.

``REMOVE_DUPLICATES`` will remove duplicated items in the list.

``REVERSE`` reverses the contents of the list in-place.

``SORT`` sorts the list in-place alphabetically.

The list subcommands ``APPEND``, ``INSERT``, ``FILTER``, ``REMOVE_AT``,
``REMOVE_ITEM``, ``REMOVE_DUPLICATES``, ``REVERSE`` and ``SORT`` may create new
values for the list within the current CMake variable scope.  Similar to the
``set()`` command, the LIST command creates new variable values in the
current scope, even if the list itself is actually defined in a parent
scope.  To propagate the results of these operations upwards, use
``set()`` with ``PARENT_SCOPE``, ``set()`` with
``CACHE INTERNAL``, or some other means of value propagation.

NOTES: A list in cmake is a ``;`` separated group of strings.  To create a
list the set command can be used.  For example, ``set(var a b c d e)``
creates a list with ``a;b;c;d;e``, and ``set(var "a b c d e")`` creates a
string or a list with one item in it.   (Note macro arguments are not
variables, and therefore cannot be used in LIST commands.)

When specifying index values, if ``<element index>`` is 0 or greater, it
is indexed from the beginning of the list, with 0 representing the
first list element.  If ``<element index>`` is -1 or lesser, it is indexed
from the end of the list, with -1 representing the last list element.
Be careful when counting with negative indices: they do not start from
0.  -0 is equivalent to 0, the first list element.

macro
-----

Start recording a macro for later invocation as a command::

 macro(<name> [arg1 [arg2 [arg3 ...]]])
   COMMAND1(ARGS ...)
   COMMAND2(ARGS ...)
   ...
 endmacro(<name>)

Define a macro named ``<name>`` that takes arguments named ``arg1``,
``arg2``, ``arg3``, (...).
Commands listed after macro, but before the matching
``endmacro()``, are not invoked until the macro is invoked.
When it is invoked, the commands recorded in the macro are first
modified by replacing formal parameters (``${arg1}``) with the arguments
passed, and then invoked as normal commands.
In addition to referencing the formal parameters you can reference the
values ``${ARGC}`` which will be set to the number of arguments passed
into the function as well as ``${ARGV0}``, ``${ARGV1}``, ``${ARGV2}``,
...  which will have the actual values of the arguments passed in.
This facilitates creating macros with optional arguments.
Additionally ``${ARGV}`` holds the list of all arguments given to the
macro and ``${ARGN}`` holds the list of arguments past the last expected
argument.
Referencing to ``${ARGV#}`` arguments beyond ``${ARGC}`` have undefined
behavior. Checking that ``${ARGC}`` is greater than ``#`` is the only
way to ensure that ``${ARGV#}`` was passed to the function as an extra
argument.

See the ``cmake_policy()`` command documentation for the behavior
of policies inside macros.

Macro Argument Caveats
^^^^^^^^^^^^^^^^^^^^^^

Note that the parameters to a macro and values such as ``ARGN`` are
not variables in the usual CMake sense.  They are string
replacements much like the C preprocessor would do with a macro.
Therefore you will NOT be able to use commands like::

 if(ARGV1) # ARGV1 is not a variable
 if(DEFINED ARGV2) # ARGV2 is not a variable
 if(ARGC GREATER 2) # ARGC is not a variable
 foreach(loop_var IN LISTS ARGN) # ARGN is not a variable

In the first case, you can use ``if(${ARGV1})``.
In the second and third case, the proper way to check if an optional
variable was passed to the macro is to use ``if(${ARGC} GREATER 2)``.
In the last case, you can use ``foreach(loop_var ${ARGN})`` but this
will skip empty arguments.
If you need to include them, you can use::

 set(list_var "${ARGN}")
 foreach(loop_var IN LISTS list_var)

Note that if you have a variable with the same name in the scope from
which the macro is called, using unreferenced names will use the
existing variable instead of the arguments. For example::

 macro(_BAR)
   foreach(arg IN LISTS ARGN)
     [...]
   endforeach()
 endmacro()

 function(_FOO)
   _bar(x y z)
 endfunction()

 _foo(a b c)

Will loop over ``a;b;c`` and not over ``x;y;z`` as one might be expecting.
If you want true CMake variables and/or better CMake scope control you
should look at the function command.

mark_as_advanced
----------------

Mark cmake cached variables as advanced.

::

 mark_as_advanced([CLEAR|FORCE] VAR [VAR2 ...])

Mark the named cached variables as advanced.  An advanced variable
will not be displayed in any of the cmake GUIs unless the show
advanced option is on.  If ``CLEAR`` is the first argument advanced
variables are changed back to unadvanced.  If ``FORCE`` is the first
argument, then the variable is made advanced.  If neither ``FORCE`` nor
``CLEAR`` is specified, new values will be marked as advanced, but if the
variable already has an advanced/non-advanced state, it will not be
changed.

It does nothing in script mode.

math
----

Mathematical expressions.

::

 math(EXPR <output-variable> <math-expression>)

``EXPR`` evaluates mathematical expression and returns result in the
output variable.  Example mathematical expression is ``5 * (10 + 13)``.
Supported operators are ``+``, ``-``, ``*``, ``/``, ``%``, ``|``, ``&``,
``^``, ``~``, ``<<``, ``>>``, and ``(...)``.  They have the same meaning
as they do in C code.

message
-------

Display a message to the user.

::

 message([<mode>] "message to display" ...)

The optional ``<mode>`` keyword determines the type of message:

::

 (none)         = Important information
 STATUS         = Incidental information
 WARNING        = CMake Warning, continue processing
 AUTHOR_WARNING = CMake Warning (dev), continue processing
 SEND_ERROR     = CMake Error, continue processing,
                               but skip generation
 FATAL_ERROR    = CMake Error, stop processing and generation
 DEPRECATION    = CMake Deprecation Error or Warning if variable
                  CMAKE_ERROR_DEPRECATED or CMAKE_WARN_DEPRECATED
                  is enabled, respectively, else no message.

The CMake command-line tool displays STATUS messages on stdout and all
other message types on stderr.  The CMake GUI displays all messages in
its log area.  The interactive dialogs (ccmake and CMakeSetup) show
STATUS messages one at a time on a status line and other messages in
interactive pop-up boxes.

CMake Warning and Error message text displays using a simple markup
language.  Non-indented text is formatted in line-wrapped paragraphs
delimited by newlines.  Indented text is considered pre-formatted.

option
------

Provides an option that the user can optionally select.

::

 option(<option_variable> "help string describing option"
        [initial value])

Provide an option for the user to select as ``ON`` or ``OFF``.  If no
initial value is provided, ``OFF`` is used.

If you have options that depend on the values of other options, see
the module help for ``CMakeDependentOption``.

return
------

Return from a file, directory or function.

::

 return()

Returns from a file, directory or function.  When this command is
encountered in an included file (via ``include()`` or
``find_package()``), it causes processing of the current file to stop
and control is returned to the including file.  If it is encountered in a
file which is not included by another file, e.g.  a ``CMakeLists.txt``,
control is returned to the parent directory if there is one.  If return is
called in a function, control is returned to the caller of the function.
Note that a macro is not a function and does not handle return like a
function does.

separate_arguments
------------------

Parse space-separated arguments into a semicolon-separated list.

::

 separate_arguments(<var> <NATIVE|UNIX|WINDOWS>_COMMAND "<args>")

Parses a UNIX- or Windows-style command-line string "<args>" and
stores a semicolon-separated list of the arguments in ``<var>``.  The
entire command line must be given in one "<args>" argument.

The ``UNIX_COMMAND`` mode separates arguments by unquoted whitespace.  It
recognizes both single-quote and double-quote pairs.  A backslash
escapes the next literal character (``\"`` is ``"``); there are no special
escapes (``\n`` is just ``n``).

The ``WINDOWS_COMMAND`` mode parses a Windows command-line using the same
syntax the runtime library uses to construct argv at startup.  It
separates arguments by whitespace that is not double-quoted.
Backslashes are literal unless they precede double-quotes.  See the
MSDN article `Parsing C Command-Line Arguments`_ for details.

The ``NATIVE_COMMAND`` mode parses a Windows command-line if the host
system is Windows, and a UNIX command-line otherwise.

::

 separate_arguments(<var>)

Convert the value of ``<var>`` to a semi-colon separated list.  All
spaces are replaced with ';'.  This helps with generating command
lines.

set_directory_properties
------------------------

Set a property of the directory.

::

 set_directory_properties(PROPERTIES prop1 value1 prop2 value2)

Set a property for the current directory and subdirectories. See
:ref:`Directory Properties` for the list of properties known
to CMake.

set_property
------------

Set a named property in a given scope.

::

 set_property(<GLOBAL                            |
               DIRECTORY [dir]                   |
               TARGET    [target1 [target2 ...]] |
               SOURCE    [src1 [src2 ...]]       |
               INSTALL   [file1 [file2 ...]]     |
               TEST      [test1 [test2 ...]]     |
               CACHE     [entry1 [entry2 ...]]>
              [APPEND] [APPEND_STRING]
              PROPERTY <name> [value1 [value2 ...]])

Set one property on zero or more objects of a scope.  The first
argument determines the scope in which the property is set.  It must
be one of the following:

``GLOBAL``
  Scope is unique and does not accept a name.

``DIRECTORY``
  Scope defaults to the current directory but another
  directory (already processed by CMake) may be named by full or
  relative path.

``TARGET``
  Scope may name zero or more existing targets.

``SOURCE``
  Scope may name zero or more source files.  Note that source
  file properties are visible only to targets added in the same
  directory (CMakeLists.txt).

``INSTALL``
  Scope may name zero or more installed file paths.
  These are made available to CPack to influence deployment.

  Both the property key and value may use generator expressions.
  Specific properties may apply to installed files and/or directories.

  Path components have to be separated by forward slashes,
  must be normalized and are case sensitive.

  To reference the installation prefix itself with a relative path use ".".

  Currently installed file properties are only defined for
  the WIX generator where the given paths are relative
  to the installation prefix.

``TEST``
  Scope may name zero or more existing tests.

``CACHE``
  Scope must name zero or more cache existing entries.

The required ``PROPERTY`` option is immediately followed by the name of
the property to set.  Remaining arguments are used to compose the
property value in the form of a semicolon-separated list.  If the
``APPEND`` option is given the list is appended to any existing property
value.  If the ``APPEND_STRING`` option is given the string is append to any
existing property value as string, i.e.  it results in a longer string
and not a list of strings.

See the ``cmake-properties(7)`` manual for a list of properties
in each scope.

set
---

Set a normal, cache, or environment variable to a given value.
See the :ref:`cmake-language(7) variables <CMake Language Variables>`
documentation for the scopes and interaction of normal variables
and cache entries.

Signatures of this command that specify a ``<value>...`` placeholder
expect zero or more arguments.  Multiple arguments will be joined as
a :ref:`;-list <CMake Language Lists>` to form the actual variable
value to be set.  Zero arguments will cause normal variables to be
unset.  See the ``unset()`` command to unset variables explicitly.

Set Normal Variable
^^^^^^^^^^^^^^^^^^^

::

 set(<variable> <value>... [PARENT_SCOPE])

Set the given ``<variable>`` in the current function or directory scope.

If the ``PARENT_SCOPE`` option is given the variable will be set in
the scope above the current scope.  Each new directory or function
creates a new scope.  This command will set the value of a variable
into the parent directory or calling function (whichever is applicable
to the case at hand). The previous state of the variable's value stays the
same in the current scope (e.g., if it was undefined before, it is still
undefined and if it had a value, it is still that value).

Set Cache Entry
^^^^^^^^^^^^^^^

::

 set(<variable> <value>... CACHE <type> <docstring> [FORCE])

Set the given cache ``<variable>`` (cache entry).  Since cache entries
are meant to provide user-settable values this does not overwrite
existing cache entries by default.  Use the ``FORCE`` option to
overwrite existing entries.

The ``<type>`` must be specified as one of:

``BOOL``
  Boolean ``ON/OFF`` value.  ``cmake-gui(1)`` offers a checkbox.

``FILEPATH``
  Path to a file on disk.  ``cmake-gui(1)`` offers a file dialog.

``PATH``
  Path to a directory on disk.  ``cmake-gui(1)`` offers a file dialog.

``STRING``
  A line of text.  ``cmake-gui(1)`` offers a text field or a
  drop-down selection if the ``STRINGS`` cache entry
  property is set.

``INTERNAL``
  A line of text.  ``cmake-gui(1)`` does not show internal entries.
  They may be used to store variables persistently across runs.
  Use of this type implies ``FORCE``.

The ``<docstring>`` must be specified as a line of text providing
a quick summary of the option for presentation to ``cmake-gui(1)``
users.

If the cache entry does not exist prior to the call or the ``FORCE``
option is given then the cache entry will be set to the given value.
Furthermore, any normal variable binding in the current scope will
be removed to expose the newly cached value to any immediately
following evaluation.

It is possible for the cache entry to exist prior to the call but
have no type set if it was created on the ``cmake(1)`` command
line by a user through the ``-D<var>=<value>`` option without
specifying a type.  In this case the ``set`` command will add the
type.  Furthermore, if the ``<type>`` is ``PATH`` or ``FILEPATH``
and the ``<value>`` provided on the command line is a relative path,
then the ``set`` command will treat the path as relative to the
current working directory and convert it to an absolute path.

Set Environment Variable
^^^^^^^^^^^^^^^^^^^^^^^^

::

 set(ENV{<variable>} <value>...)

Set the current process environment ``<variable>`` to the given value.

site_name
---------

Set the given variable to the name of the computer.

::

 site_name(variable)

string
------

String operations.

Search and Replace
^^^^^^^^^^^^^^^^^^

FIND
""""

::

 string(FIND <string> <substring> <output variable> [REVERSE])

Return the position where the given substring was found in
the supplied string.  If the ``REVERSE`` flag was used, the command will
search for the position of the last occurrence of the specified
substring.  If the substring is not found, a position of -1 is returned.

REPLACE
"""""""

::

 string(REPLACE <match_string>
        <replace_string> <output variable>
        <input> [<input>...])

Replace all occurrences of ``match_string`` in the input
with ``replace_string`` and store the result in the output.

Regular Expressions
^^^^^^^^^^^^^^^^^^^

REGEX MATCH
"""""""""""

::

 string(REGEX MATCH <regular_expression>
        <output variable> <input> [<input>...])

Match the regular expression once and store the match in the output variable.
All ``<input>`` arguments are concatenated before matching.

REGEX MATCHALL
""""""""""""""

::

 string(REGEX MATCHALL <regular_expression>
        <output variable> <input> [<input>...])

Match the regular expression as many times as possible and store the matches
in the output variable as a list.
All ``<input>`` arguments are concatenated before matching.

REGEX REPLACE
"""""""""""""

::

 string(REGEX REPLACE <regular_expression>
        <replace_expression> <output variable>
        <input> [<input>...])

Match the regular expression as many times as possible and substitute the
replacement expression for the match in the output.
All ``<input>`` arguments are concatenated before matching.

The replace expression may refer to paren-delimited subexpressions of the
match using ``\1``, ``\2``, ..., ``\9``.  Note that two backslashes (``\\1``)
are required in CMake code to get a backslash through argument parsing.

Regex Specification
"""""""""""""""""""

The following characters have special meaning in regular expressions:

``^``
  Matches at beginning of input
``$``
  Matches at end of input
``.``
  Matches any single character
``[ ]``
  Matches any character(s) inside the brackets
``[^ ]``
  Matches any character(s) not inside the brackets
``-``
  Inside brackets, specifies an inclusive range between
  characters on either side e.g. ``[a-f]`` is ``[abcdef]``
  To match a literal ``-`` using brackets, make it the first
  or the last character e.g. ``[+*/-]`` matches basic
  mathematical operators.
``*``
  Matches preceding pattern zero or more times
``+``
  Matches preceding pattern one or more times
``?``
  Matches preceding pattern zero or once only
``|``
  Matches a pattern on either side of the ``|``
``()``
  Saves a matched subexpression, which can be referenced
  in the ``REGEX REPLACE`` operation. Additionally it is saved
  by all regular expression-related commands, including
  e.g. ``if(MATCHES)``, in the variables
  ``CMAKE_MATCH_<n>`` for ``<n>`` 0..9.

``*``, ``+`` and ``?`` have higher precedence than concatenation.  ``|``
has lower precedence than concatenation.  This means that the regular
expression ``^ab+d$`` matches ``abbd`` but not ``ababd``, and the regular
expression ``^(ab|cd)$`` matches ``ab`` but not ``abd``.

Manipulation
^^^^^^^^^^^^

APPEND
""""""

::

 string(APPEND <string variable> [<input>...])

Append all the input arguments to the string.

CONCAT
""""""

::

 string(CONCAT <output variable> [<input>...])

Concatenate all the input arguments together and store
the result in the named output variable.

TOLOWER
"""""""

::

 string(TOLOWER <string1> <output variable>)

Convert string to lower characters.

TOUPPER
"""""""

::

 string(TOUPPER <string1> <output variable>)

Convert string to upper characters.

LENGTH
""""""

::

 string(LENGTH <string> <output variable>)

Store in an output variable a given string's length.

SUBSTRING
"""""""""

::

 string(SUBSTRING <string> <begin> <length> <output variable>)

Store in an output variable a substring of a given string.  If length is
``-1`` the remainder of the string starting at begin will be returned.
If string is shorter than length then end of string is used instead.

.. note::
  CMake 3.1 and below reported an error if length pointed past
  the end of string.

STRIP
"""""

::

 string(STRIP <string> <output variable>)

Store in an output variable a substring of a given string with leading and
trailing spaces removed.

GENEX_STRIP
"""""""""""

::

 string(GENEX_STRIP <input string> <output variable>)

Strip any ``generator expressions``
from the ``input string`` and store the result in the ``output variable``.

Comparison
^^^^^^^^^^

::

 string(COMPARE LESS <string1> <string2> <output variable>)
 string(COMPARE GREATER <string1> <string2> <output variable>)
 string(COMPARE EQUAL <string1> <string2> <output variable>)
 string(COMPARE NOTEQUAL <string1> <string2> <output variable>)
 string(COMPARE LESS_EQUAL <string1> <string2> <output variable>)
 string(COMPARE GREATER_EQUAL <string1> <string2> <output variable>)

Compare the strings and store true or false in the output variable.

Hashing
^^^^^^^

::

 string(<HASH> <output variable> <input>)

Compute a cryptographic hash of the input string.
The supported ``<HASH>`` algorithm names are:

``MD5``
  Message-Digest Algorithm 5, RFC 1321.
``SHA1``
  US Secure Hash Algorithm 1, RFC 3174.
``SHA224``
  US Secure Hash Algorithms, RFC 4634.
``SHA256``
  US Secure Hash Algorithms, RFC 4634.
``SHA384``
  US Secure Hash Algorithms, RFC 4634.
``SHA512``
  US Secure Hash Algorithms, RFC 4634.
``SHA3_224``
  Keccak SHA-3.
``SHA3_256``
  Keccak SHA-3.
``SHA3_384``
  Keccak SHA-3.
``SHA3_512``
  Keccak SHA-3.

Generation
^^^^^^^^^^

ASCII
"""""

::

 string(ASCII <number> [<number> ...] <output variable>)

Convert all numbers into corresponding ASCII characters.

CONFIGURE
"""""""""

::

 string(CONFIGURE <string1> <output variable>
        [@ONLY] [ESCAPE_QUOTES])

Transform a string like ``configure_file()`` transforms a file.

RANDOM
""""""

::

 string(RANDOM [LENGTH <length>] [ALPHABET <alphabet>]
        [RANDOM_SEED <seed>] <output variable>)

Return a random string of given length consisting of
characters from the given alphabet.  Default length is 5 characters
and default alphabet is all numbers and upper and lower case letters.
If an integer ``RANDOM_SEED`` is given, its value will be used to seed the
random number generator.

TIMESTAMP
"""""""""

::

 string(TIMESTAMP <output variable> [<format string>] [UTC])

Write a string representation of the current date
and/or time to the output variable.

Should the command be unable to obtain a timestamp the output variable
will be set to the empty string "".

The optional ``UTC`` flag requests the current date/time representation to
be in Coordinated Universal Time (UTC) rather than local time.

The optional ``<format string>`` may contain the following format
specifiers:

::

 %%        A literal percent sign (%).
 %d        The day of the current month (01-31).
 %H        The hour on a 24-hour clock (00-23).
 %I        The hour on a 12-hour clock (01-12).
 %j        The day of the current year (001-366).
 %m        The month of the current year (01-12).
 %b        Abbreviated month name (e.g. Oct).
 %M        The minute of the current hour (00-59).
 %s        Seconds since midnight (UTC) 1-Jan-1970 (UNIX time).
 %S        The second of the current minute.
           60 represents a leap second. (00-60)
 %U        The week number of the current year (00-53).
 %w        The day of the current week. 0 is Sunday. (0-6)
 %a        Abbreviated weekday name (e.g. Fri).
 %y        The last two digits of the current year (00-99)
 %Y        The current year.

Unknown format specifiers will be ignored and copied to the output
as-is.

If no explicit ``<format string>`` is given it will default to:

::

 %Y-%m-%dT%H:%M:%S    for local time.
 %Y-%m-%dT%H:%M:%SZ   for UTC.

::

 string(MAKE_C_IDENTIFIER <input string> <output variable>)

Write a string which can be used as an identifier in C.

.. note::

  If the ``SOURCE_DATE_EPOCH`` environment variable is set,
  its value will be used instead of the current time.
  See https://reproducible-builds.org/specs/source-date-epoch/ for details.

UUID
""""

::

 string(UUID <output variable> NAMESPACE <namespace> NAME <name>
        TYPE <MD5|SHA1> [UPPER])

Create a univerally unique identifier (aka GUID) as per RFC4122
based on the hash of the combined values of ``<namespace>``
(which itself has to be a valid UUID) and ``<name>``.
The hash algorithm can be either ``MD5`` (Version 3 UUID) or
``SHA1`` (Version 5 UUID).
A UUID has the format ``xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx``
where each `x` represents a lower case hexadecimal character.
Where required an uppercase representation can be requested
with the optional ``UPPER`` flag.

unset
-----

Unset a variable, cache variable, or environment variable.

::

 unset(<variable> [CACHE | PARENT_SCOPE])

Removes the specified variable causing it to become undefined.  If
``CACHE`` is present then the variable is removed from the cache instead
of the current scope.

If ``PARENT_SCOPE`` is present then the variable is removed from the scope
above the current scope.  See the same option in the ``set()`` command
for further details.

``<variable>`` can be an environment variable such as:

::

 unset(ENV{LD_LIBRARY_PATH})

in which case the variable will be removed from the current
environment.

variable_watch
--------------

Watch the CMake variable for change.

::

 variable_watch(<variable name> [<command to execute>])

If the specified variable changes, the message will be printed about
the variable being changed.  If the command is specified, the command
will be executed.  The command will receive the following arguments:
COMMAND(<variable> <access> <value> <current list file> <stack>)

while
-----

Evaluate a group of commands while a condition is true

::

 while(condition)
   COMMAND1(ARGS ...)
   COMMAND2(ARGS ...)
   ...
 endwhile(condition)

All commands between while and the matching ``endwhile()`` are recorded
without being invoked.  Once the ``endwhile()`` is evaluated, the
recorded list of commands is invoked as long as the condition is true.  The
condition is evaluated using the same logic as the ``if()`` command.

Project Commands
================

These commands are available only in CMake projects.

add_compile_options
-------------------

Adds options to the compilation of source files.

::

 add_compile_options(<option> ...)

Adds options to the compiler command line for targets in the current
directory and below that are added after this command is invoked.
See documentation of the ``directory`` and
``target`` ``COMPILE_OPTIONS`` properties.

This command can be used to add any options, but alternative commands
exist to add preprocessor definitions (``target_compile_definitions()``
and ``add_definitions()``) or include directories
(``target_include_directories()`` and ``include_directories()``).

Arguments to ``add_compile_options`` may use "generator expressions" with
the syntax ``$<...>``.  See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

add_custom_command
------------------

Add a custom build rule to the generated build system.

There are two main signatures for ``add_custom_command``.

Generating Files
^^^^^^^^^^^^^^^^

The first signature is for adding a custom command to produce an output::

 add_custom_command(OUTPUT output1 [output2 ...]
                    COMMAND command1 [ARGS] [args1...]
                    [COMMAND command2 [ARGS] [args2...] ...]
                    [MAIN_DEPENDENCY depend]
                    [DEPENDS [depends...]]
                    [BYPRODUCTS [files...]]
                    [IMPLICIT_DEPENDS <lang1> depend1
                                     [<lang2> depend2] ...]
                    [WORKING_DIRECTORY dir]
                    [COMMENT comment]
                    [DEPFILE depfile]
                    [VERBATIM] [APPEND] [USES_TERMINAL]
                    [COMMAND_EXPAND_LISTS])

This defines a command to generate specified ``OUTPUT`` file(s).
A target created in the same directory (``CMakeLists.txt`` file)
that specifies any output of the custom command as a source file
is given a rule to generate the file using the command at build time.
Do not list the output in more than one independent target that
may build in parallel or the two instances of the rule may conflict
(instead use the ``add_custom_target()`` command to drive the
command and make the other targets depend on that one).
In makefile terms this creates a new target in the following form::

 OUTPUT: MAIN_DEPENDENCY DEPENDS
         COMMAND

The options are:

``APPEND``
  Append the ``COMMAND`` and ``DEPENDS`` option values to the custom
  command for the first output specified.  There must have already
  been a previous call to this command with the same output.
  The ``COMMENT``, ``MAIN_DEPENDENCY``, and ``WORKING_DIRECTORY``
  options are currently ignored when APPEND is given, but may be
  used in the future.

``BYPRODUCTS``
  Specify the files the command is expected to produce but whose
  modification time may or may not be newer than the dependencies.
  If a byproduct name is a relative path it will be interpreted
  relative to the build tree directory corresponding to the
  current source directory.
  Each byproduct file will be marked with the ``GENERATED``
  source file property automatically.

  Explicit specification of byproducts is supported by the
  ``Ninja`` generator to tell the ``ninja`` build tool
  how to regenerate byproducts when they are missing.  It is
  also useful when other build rules (e.g. custom commands)
  depend on the byproducts.  Ninja requires a build rule for any
  generated file on which another rule depends even if there are
  order-only dependencies to ensure the byproducts will be
  available before their dependents build.

  The ``BYPRODUCTS`` option is ignored on non-Ninja generators
  except to mark byproducts ``GENERATED``.

``COMMAND``
  Specify the command-line(s) to execute at build time.
  If more than one ``COMMAND`` is specified they will be executed in order,
  but *not* necessarily composed into a stateful shell or batch script.
  (To run a full script, use the ``configure_file()`` command or the
  ``file(GENERATE)`` command to create it, and then specify
  a ``COMMAND`` to launch it.)
  The optional ``ARGS`` argument is for backward compatibility and
  will be ignored.

  If ``COMMAND`` specifies an executable target name (created by the
  ``add_executable()`` command) it will automatically be replaced
  by the location of the executable created at build time. If set, the
  ``CROSSCOMPILING_EMULATOR`` executable target property will
  also be prepended to the command to allow the executable to run on
  the host.
  (Use the ``TARGET_FILE``
  ``generator expression`` to
  reference an executable later in the command line.)
  Additionally a target-level dependency will be added so that the
  executable target will be built before any target using this custom
  command.  However this does NOT add a file-level dependency that
  would cause the custom command to re-run whenever the executable is
  recompiled.

  Arguments to ``COMMAND`` may use
  ``generator expressions``.
  References to target names in generator expressions imply target-level
  dependencies, but NOT file-level dependencies.  List target names with
  the ``DEPENDS`` option to add file-level dependencies.

``COMMENT``
  Display the given message before the commands are executed at
  build time.

``DEPENDS``
  Specify files on which the command depends.  If any dependency is
  an ``OUTPUT`` of another custom command in the same directory
  (``CMakeLists.txt`` file) CMake automatically brings the other
  custom command into the target in which this command is built.
  If ``DEPENDS`` is not specified the command will run whenever
  the ``OUTPUT`` is missing; if the command does not actually
  create the ``OUTPUT`` then the rule will always run.
  If ``DEPENDS`` specifies any target (created by the
  ``add_custom_target()``, ``add_executable()``, or
  ``add_library()`` command) a target-level dependency is
  created to make sure the target is built before any target
  using this custom command.  Additionally, if the target is an
  executable or library a file-level dependency is created to
  cause the custom command to re-run whenever the target is
  recompiled.

  Arguments to ``DEPENDS`` may use
  ``generator expressions``.

``COMMAND_EXPAND_LISTS``
  Lists in ``COMMAND`` arguments will be expanded, including those
  created with
  ``generator expressions``,
  allowing ``COMMAND`` arguments such as
  ``${CC} "-I$<JOIN:$<TARGET_PROPERTY:foo,INCLUDE_DIRECTORIES>,;-I>" foo.cc``
  to be properly expanded.

``IMPLICIT_DEPENDS``
  Request scanning of implicit dependencies of an input file.
  The language given specifies the programming language whose
  corresponding dependency scanner should be used.
  Currently only ``C`` and ``CXX`` language scanners are supported.
  The language has to be specified for every file in the
  ``IMPLICIT_DEPENDS`` list.  Dependencies discovered from the
  scanning are added to those of the custom command at build time.
  Note that the ``IMPLICIT_DEPENDS`` option is currently supported
  only for Makefile generators and will be ignored by other generators.

``MAIN_DEPENDENCY``
  Specify the primary input source file to the command.  This is
  treated just like any value given to the ``DEPENDS`` option
  but also suggests to Visual Studio generators where to hang
  the custom command.  At most one custom command may specify a
  given source file as its main dependency.

``OUTPUT``
  Specify the output files the command is expected to produce.
  If an output name is a relative path it will be interpreted
  relative to the build tree directory corresponding to the
  current source directory.
  Each output file will be marked with the ``GENERATED``
  source file property automatically.
  If the output of the custom command is not actually created
  as a file on disk it should be marked with the ``SYMBOLIC``
  source file property.

``USES_TERMINAL``
  The command will be given direct access to the terminal if possible.
  With the ``Ninja`` generator, this places the command in
  the ``console`` ``pool``.

``VERBATIM``
  All arguments to the commands will be escaped properly for the
  build tool so that the invoked command receives each argument
  unchanged.  Note that one level of escapes is still used by the
  CMake language processor before add_custom_command even sees the
  arguments.  Use of ``VERBATIM`` is recommended as it enables
  correct behavior.  When ``VERBATIM`` is not given the behavior
  is platform specific because there is no protection of
  tool-specific special characters.

``WORKING_DIRECTORY``
  Execute the command with the given current working directory.
  If it is a relative path it will be interpreted relative to the
  build tree directory corresponding to the current source directory.

``DEPFILE``
  Specify a ``.d`` depfile for the ``Ninja`` generator.
  A ``.d`` file holds dependencies usually emitted by the custom
  command itself.
  Using ``DEPFILE`` with other generators than Ninja is an error.

Build Events
^^^^^^^^^^^^

The second signature adds a custom command to a target such as a
library or executable.  This is useful for performing an operation
before or after building the target.  The command becomes part of the
target and will only execute when the target itself is built.  If the
target is already built, the command will not execute.

::

 add_custom_command(TARGET <target>
                    PRE_BUILD | PRE_LINK | POST_BUILD
                    COMMAND command1 [ARGS] [args1...]
                    [COMMAND command2 [ARGS] [args2...] ...]
                    [BYPRODUCTS [files...]]
                    [WORKING_DIRECTORY dir]
                    [COMMENT comment]
                    [VERBATIM] [USES_TERMINAL])

This defines a new command that will be associated with building the
specified ``<target>``.  The ``<target>`` must be defined in the current
directory; targets defined in other directories may not be specified.

When the command will happen is determined by which
of the following is specified:

``PRE_BUILD``
  Run before any other rules are executed within the target.
  This is supported only on Visual Studio 8 or later.
  For all other generators ``PRE_BUILD`` will be treated as
  ``PRE_LINK``.
``PRE_LINK``
  Run after sources have been compiled but before linking the binary
  or running the librarian or archiver tool of a static library.
  This is not defined for targets created by the
  ``add_custom_target()`` command.
``POST_BUILD``
  Run after all other rules within the target have been executed.

add_custom_target
-----------------

Add a target with no output so it will always be built.

::

 add_custom_target(Name [ALL] [command1 [args1...]]
                   [COMMAND command2 [args2...] ...]
                   [DEPENDS depend depend depend ... ]
                   [BYPRODUCTS [files...]]
                   [WORKING_DIRECTORY dir]
                   [COMMENT comment]
                   [VERBATIM] [USES_TERMINAL]
                   [COMMAND_EXPAND_LISTS]
                   [SOURCES src1 [src2...]])

Adds a target with the given name that executes the given commands.
The target has no output file and is *always considered out of date*
even if the commands try to create a file with the name of the target.
Use the ``add_custom_command()`` command to generate a file with
dependencies.  By default nothing depends on the custom target.  Use
the ``add_dependencies()`` command to add dependencies to or
from other targets.

The options are:

``ALL``
  Indicate that this target should be added to the default build
  target so that it will be run every time (the command cannot be
  called ``ALL``).

``BYPRODUCTS``
  Specify the files the command is expected to produce but whose
  modification time may or may not be updated on subsequent builds.
  If a byproduct name is a relative path it will be interpreted
  relative to the build tree directory corresponding to the
  current source directory.
  Each byproduct file will be marked with the ``GENERATED``
  source file property automatically.

  Explicit specification of byproducts is supported by the
  ``Ninja`` generator to tell the ``ninja`` build tool
  how to regenerate byproducts when they are missing.  It is
  also useful when other build rules (e.g. custom commands)
  depend on the byproducts.  Ninja requires a build rule for any
  generated file on which another rule depends even if there are
  order-only dependencies to ensure the byproducts will be
  available before their dependents build.

  The ``BYPRODUCTS`` option is ignored on non-Ninja generators
  except to mark byproducts ``GENERATED``.

``COMMAND``
  Specify the command-line(s) to execute at build time.
  If more than one ``COMMAND`` is specified they will be executed in order,
  but *not* necessarily composed into a stateful shell or batch script.
  (To run a full script, use the ``configure_file()`` command or the
  ``file(GENERATE)`` command to create it, and then specify
  a ``COMMAND`` to launch it.)

  If ``COMMAND`` specifies an executable target name (created by the
  ``add_executable()`` command) it will automatically be replaced
  by the location of the executable created at build time. If set, the
  ``CROSSCOMPILING_EMULATOR`` executable target property will
  also be prepended to the command to allow the executable to run on
  the host.
  Additionally a target-level dependency will be added so that the
  executable target will be built before this custom target.

  Arguments to ``COMMAND`` may use
  ``generator expressions``.
  References to target names in generator expressions imply target-level
  dependencies.

  The command and arguments are optional and if not specified an empty
  target will be created.

``COMMENT``
  Display the given message before the commands are executed at
  build time.

``DEPENDS``
  Reference files and outputs of custom commands created with
  ``add_custom_command()`` command calls in the same directory
  (``CMakeLists.txt`` file).  They will be brought up to date when
  the target is built.

  Use the ``add_dependencies()`` command to add dependencies
  on other targets.

``COMMAND_EXPAND_LISTS``
  Lists in ``COMMAND`` arguments will be expanded, including those
  created with
  ``generator expressions``,
  allowing ``COMMAND`` arguments such as
  ``${CC} "-I$<JOIN:$<TARGET_PROPERTY:foo,INCLUDE_DIRECTORIES>,;-I>" foo.cc``
  to be properly expanded.

``SOURCES``
  Specify additional source files to be included in the custom target.
  Specified source files will be added to IDE project files for
  convenience in editing even if they have no build rules.

``VERBATIM``
  All arguments to the commands will be escaped properly for the
  build tool so that the invoked command receives each argument
  unchanged.  Note that one level of escapes is still used by the
  CMake language processor before ``add_custom_target`` even sees
  the arguments.  Use of ``VERBATIM`` is recommended as it enables
  correct behavior.  When ``VERBATIM`` is not given the behavior
  is platform specific because there is no protection of
  tool-specific special characters.

``USES_TERMINAL``
  The command will be given direct access to the terminal if possible.
  With the ``Ninja`` generator, this places the command in
  the ``console`` ``pool``.

``WORKING_DIRECTORY``
  Execute the command with the given current working directory.
  If it is a relative path it will be interpreted relative to the
  build tree directory corresponding to the current source directory.

add_definitions
---------------

Adds -D define flags to the compilation of source files.

::

 add_definitions(-DFOO -DBAR ...)

Adds definitions to the compiler command line for targets in the current
directory and below (whether added before or after this command is invoked).
This command can be used to add any flags, but it is intended to add
preprocessor definitions (see the ``add_compile_options()`` command
to add other flags).
Flags beginning in -D or /D that look like preprocessor definitions are
automatically added to the ``COMPILE_DEFINITIONS`` directory
property for the current directory.  Definitions with non-trivial values
may be left in the set of flags instead of being converted for reasons of
backwards compatibility.  See documentation of the
``directory``,
``target``,
``source file`` ``COMPILE_DEFINITIONS``
properties for details on adding preprocessor definitions to specific
scopes and configurations.

See the ``cmake-buildsystem(7)`` manual for more on defining
buildsystem properties.

add_dependencies
----------------

Add a dependency between top-level targets.

::

 add_dependencies(<target> [<target-dependency>]...)

Make a top-level ``<target>`` depend on other top-level targets to
ensure that they build before ``<target>`` does.  A top-level target
is one created by one of the ``add_executable()``,
``add_library()``, or ``add_custom_target()`` commands
(but not targets generated by CMake like ``install``).

Dependencies added to an :ref:`imported target <Imported Targets>`
or an :ref:`interface library <Interface Libraries>` are followed
transitively in its place since the target itself does not build.

See the ``DEPENDS`` option of ``add_custom_target()`` and
``add_custom_command()`` commands for adding file-level
dependencies in custom rules.  See the ``OBJECT_DEPENDS``
source file property to add file-level dependencies to object files.

add_executable
--------------

Add an executable to the project using the specified source files.

::

 add_executable(<name> [WIN32] [MACOSX_BUNDLE]
                [EXCLUDE_FROM_ALL]
                source1 [source2 ...])

Adds an executable target called ``<name>`` to be built from the source
files listed in the command invocation.  The ``<name>`` corresponds to the
logical target name and must be globally unique within a project.  The
actual file name of the executable built is constructed based on
conventions of the native platform (such as ``<name>.exe`` or just
``<name>``).

By default the executable file will be created in the build tree
directory corresponding to the source tree directory in which the
command was invoked.  See documentation of the
``RUNTIME_OUTPUT_DIRECTORY`` target property to change this
location.  See documentation of the ``OUTPUT_NAME`` target property
to change the ``<name>`` part of the final file name.

If ``WIN32`` is given the property ``WIN32_EXECUTABLE`` will be
set on the target created.  See documentation of that target property for
details.

If ``MACOSX_BUNDLE`` is given the corresponding property will be set on
the created target.  See documentation of the ``MACOSX_BUNDLE``
target property for details.

If ``EXCLUDE_FROM_ALL`` is given the corresponding property will be set on
the created target.  See documentation of the ``EXCLUDE_FROM_ALL``
target property for details.

Source arguments to ``add_executable`` may use "generator expressions" with
the syntax ``$<...>``.  See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

See also ``HEADER_FILE_ONLY`` on what to do if some sources are
pre-processed, and you want to have the original sources reachable from
within IDE.

--------------------------------------------------------------------------

::

 add_executable(<name> IMPORTED [GLOBAL])

An :ref:`IMPORTED executable target <Imported Targets>` references an
executable file located outside the project.  No rules are generated to
build it, and the ``IMPORTED`` target property is ``True``.  The
target name has scope in the directory in which it is created and below, but
the ``GLOBAL`` option extends visibility.  It may be referenced like any
target built within the project.  ``IMPORTED`` executables are useful
for convenient reference from commands like ``add_custom_command()``.
Details about the imported executable are specified by setting properties
whose names begin in ``IMPORTED_``.  The most important such property is
``IMPORTED_LOCATION`` (and its per-configuration version
``IMPORTED_LOCATION_<CONFIG>``) which specifies the location of
the main executable file on disk.  See documentation of the ``IMPORTED_*``
properties for more information.

--------------------------------------------------------------------------

::

 add_executable(<name> ALIAS <target>)

Creates an :ref:`Alias Target <Alias Targets>`, such that ``<name>`` can
be used to refer to ``<target>`` in subsequent commands.  The ``<name>``
does not appear in the generated buildsystem as a make target.  The
``<target>`` may not be an :ref:`Imported Target <Imported Targets>` or an
``ALIAS``.  ``ALIAS`` targets can be used as targets to read properties
from, executables for custom commands and custom targets.  They can also be
tested for existence with the regular ``if(TARGET)`` subcommand.
The ``<name>`` may not be used to modify properties of ``<target>``, that
is, it may not be used as the operand of ``set_property()``,
``set_target_properties()``, ``target_link_libraries()`` etc.
An ``ALIAS`` target may not be installed or exported.

add_library
-----------

Add a library to the project using the specified source files.

Normal Libraries
^^^^^^^^^^^^^^^^

::

 add_library(<name> [STATIC | SHARED | MODULE]
             [EXCLUDE_FROM_ALL]
             source1 [source2 ...])

Adds a library target called ``<name>`` to be built from the source files
listed in the command invocation.  The ``<name>`` corresponds to the
logical target name and must be globally unique within a project.  The
actual file name of the library built is constructed based on
conventions of the native platform (such as ``lib<name>.a`` or
``<name>.lib``).

``STATIC``, ``SHARED``, or ``MODULE`` may be given to specify the type of
library to be created.  ``STATIC`` libraries are archives of object files
for use when linking other targets.  ``SHARED`` libraries are linked
dynamically and loaded at runtime.  ``MODULE`` libraries are plugins that
are not linked into other targets but may be loaded dynamically at runtime
using dlopen-like functionality.  If no type is given explicitly the
type is ``STATIC`` or ``SHARED`` based on whether the current value of the
variable ``BUILD_SHARED_LIBS`` is ``ON``.  For ``SHARED`` and
``MODULE`` libraries the ``POSITION_INDEPENDENT_CODE`` target
property is set to ``ON`` automatically.
A ``SHARED`` or ``STATIC`` library may be marked with the ``FRAMEWORK``
target property to create an OS X Framework.

If a library does not export any symbols, it must not be declared as a
``SHARED`` library.  For example, a Windows resource DLL or a managed C++/CLI
DLL that exports no unmanaged symbols would need to be a ``MODULE`` library.
This is because CMake expects a ``SHARED`` library to always have an
associated import library on Windows.

By default the library file will be created in the build tree directory
corresponding to the source tree directory in which the command was
invoked.  See documentation of the ``ARCHIVE_OUTPUT_DIRECTORY``,
``LIBRARY_OUTPUT_DIRECTORY``, and
``RUNTIME_OUTPUT_DIRECTORY`` target properties to change this
location.  See documentation of the ``OUTPUT_NAME`` target
property to change the ``<name>`` part of the final file name.

If ``EXCLUDE_FROM_ALL`` is given the corresponding property will be set on
the created target.  See documentation of the ``EXCLUDE_FROM_ALL``
target property for details.

Source arguments to ``add_library`` may use "generator expressions" with
the syntax ``$<...>``.  See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

See also ``HEADER_FILE_ONLY`` on what to do if some sources are
pre-processed, and you want to have the original sources reachable from
within IDE.

Imported Libraries
^^^^^^^^^^^^^^^^^^

::

 add_library(<name> <SHARED|STATIC|MODULE|OBJECT|UNKNOWN> IMPORTED
             [GLOBAL])

An :ref:`IMPORTED library target <Imported Targets>` references a library
file located outside the project.  No rules are generated to build it, and
the ``IMPORTED`` target property is ``True``.  The target name has
scope in the directory in which it is created and below, but the ``GLOBAL``
option extends visibility.  It may be referenced like any target built
within the project.  ``IMPORTED`` libraries are useful for convenient
reference from commands like ``target_link_libraries()``.  Details
about the imported library are specified by setting properties whose names
begin in ``IMPORTED_`` and ``INTERFACE_``.  The most important such
property is ``IMPORTED_LOCATION`` (and its per-configuration
variant ``IMPORTED_LOCATION_<CONFIG>``) which specifies the
location of the main library file on disk.  See documentation of the
``IMPORTED_*`` and ``INTERFACE_*`` properties for more information.

Object Libraries
^^^^^^^^^^^^^^^^

::

 add_library(<name> OBJECT <src>...)

Creates an :ref:`Object Library <Object Libraries>`.  An object library
compiles source files but does not archive or link their object files into a
library.  Instead other targets created by ``add_library()`` or
``add_executable()`` may reference the objects using an expression of the
form ``$<TARGET_OBJECTS:objlib>`` as a source, where ``objlib`` is the
object library name.  For example:

 add_library(... $<TARGET_OBJECTS:objlib> ...)
 add_executable(... $<TARGET_OBJECTS:objlib> ...)

will include objlib's object files in a library and an executable
along with those compiled from their own sources.  Object libraries
may contain only sources that compile, header files, and other files
that would not affect linking of a normal library (e.g. ``.txt``).
They may contain custom commands generating such sources, but not
``PRE_BUILD``, ``PRE_LINK``, or ``POST_BUILD`` commands.  Object libraries
cannot be linked.  Some native build systems may not like targets that
have only object files, so consider adding at least one real source file
to any target that references ``$<TARGET_OBJECTS:objlib>``.

Alias Libraries
^^^^^^^^^^^^^^^

::

 add_library(<name> ALIAS <target>)

Creates an :ref:`Alias Target <Alias Targets>`, such that ``<name>`` can be
used to refer to ``<target>`` in subsequent commands.  The ``<name>`` does
not appear in the generated buildsystem as a make target.  The ``<target>``
may not be an :ref:`Imported Target <Imported Targets>` or an ``ALIAS``.
``ALIAS`` targets can be used as linkable targets and as targets to
read properties from.  They can also be tested for existence with the
regular ``if(TARGET)`` subcommand.  The ``<name>`` may not be used
to modify properties of ``<target>``, that is, it may not be used as the
operand of ``set_property()``, ``set_target_properties()``,
``target_link_libraries()`` etc.  An ``ALIAS`` target may not be
installed or exported.

Interface Libraries
^^^^^^^^^^^^^^^^^^^

::

 add_library(<name> INTERFACE [IMPORTED [GLOBAL]])

Creates an :ref:`Interface Library <Interface Libraries>`.  An ``INTERFACE``
library target does not directly create build output, though it may
have properties set on it and it may be installed, exported and
imported. Typically the ``INTERFACE_*`` properties are populated on
the interface target using the commands:

* ``set_property()``,
* ``target_link_libraries(INTERFACE)``,
* ``target_include_directories(INTERFACE)``,
* ``target_compile_options(INTERFACE)``,
* ``target_compile_definitions(INTERFACE)``, and
* ``target_sources(INTERFACE)``,

and then it is used as an argument to ``target_link_libraries()``
like any other target.

An ``INTERFACE`` :ref:`Imported Target <Imported Targets>` may also be
created with this signature.  An ``IMPORTED`` library target references a
library defined outside the project.  The target name has scope in the
directory in which it is created and below, but the ``GLOBAL`` option
extends visibility.  It may be referenced like any target built within
the project.  ``IMPORTED`` libraries are useful for convenient reference
from commands like ``target_link_libraries()``.

add_subdirectory
----------------

Add a subdirectory to the build.

::

 add_subdirectory(source_dir [binary_dir]
                  [EXCLUDE_FROM_ALL])

Add a subdirectory to the build.  The source_dir specifies the
directory in which the source CMakeLists.txt and code files are
located.  If it is a relative path it will be evaluated with respect
to the current directory (the typical usage), but it may also be an
absolute path.  The ``binary_dir`` specifies the directory in which to
place the output files.  If it is a relative path it will be evaluated
with respect to the current output directory, but it may also be an
absolute path.  If ``binary_dir`` is not specified, the value of
``source_dir``, before expanding any relative path, will be used (the
typical usage).  The CMakeLists.txt file in the specified source
directory will be processed immediately by CMake before processing in
the current input file continues beyond this command.

If the ``EXCLUDE_FROM_ALL`` argument is provided then targets in the
subdirectory will not be included in the ``ALL`` target of the parent
directory by default, and will be excluded from IDE project files.
Users must explicitly build targets in the subdirectory.  This is
meant for use when the subdirectory contains a separate part of the
project that is useful but not necessary, such as a set of examples.
Typically the subdirectory should contain its own ``project()``
command invocation so that a full build system will be generated in the
subdirectory (such as a VS IDE solution file).  Note that inter-target
dependencies supercede this exclusion.  If a target built by the
parent project depends on a target in the subdirectory, the dependee
target will be included in the parent project build system to satisfy
the dependency.

add_test
--------

Add a test to the project to be run by ``ctest(1)``.

::

 add_test(NAME <name> COMMAND <command> [<arg>...]
          [CONFIGURATIONS <config>...]
          [WORKING_DIRECTORY <dir>])

Add a test called ``<name>``.  The test name may not contain spaces,
quotes, or other characters special in CMake syntax.  The options are:

``COMMAND``
  Specify the test command-line.  If ``<command>`` specifies an
  executable target (created by ``add_executable()``) it will
  automatically be replaced by the location of the executable created
  at build time.

``CONFIGURATIONS``
  Restrict execution of the test only to the named configurations.

``WORKING_DIRECTORY``
  Set the ``WORKING_DIRECTORY`` test property to
  specify the working directory in which to execute the test.
  If not specified the test will be run with the current working
  directory set to the build directory corresponding to the
  current source directory.

The given test command is expected to exit with code ``0`` to pass and
non-zero to fail, or vice-versa if the ``WILL_FAIL`` test
property is set.  Any output written to stdout or stderr will be
captured by ``ctest(1)`` but does not affect the pass/fail status
unless the ``PASS_REGULAR_EXPRESSION`` or
``FAIL_REGULAR_EXPRESSION`` test property is used.

The ``COMMAND`` and ``WORKING_DIRECTORY`` options may use "generator
expressions" with the syntax ``$<...>``.  See the
``cmake-generator-expressions(7)`` manual for available expressions.

Example usage::

 add_test(NAME mytest
          COMMAND testDriver --config $<CONFIGURATION>
                             --exe $<TARGET_FILE:myexe>)

This creates a test ``mytest`` whose command runs a ``testDriver`` tool
passing the configuration name and the full path to the executable
file produced by target ``myexe``.

.. note::

  CMake will generate tests only if the ``enable_testing()``
  command has been invoked.  The ``CTest`` module invokes the
  command automatically when the ``BUILD_TESTING`` option is ``ON``.

---------------------------------------------------------------------

::

 add_test(<name> <command> [<arg>...])

Add a test called ``<name>`` with the given command-line.  Unlike
the above ``NAME`` signature no transformation is performed on the
command-line to support target names or generator expressions.

aux_source_directory
--------------------

Find all source files in a directory.

::

 aux_source_directory(<dir> <variable>)

Collects the names of all the source files in the specified directory
and stores the list in the ``<variable>`` provided.  This command is
intended to be used by projects that use explicit template
instantiation.  Template instantiation files can be stored in a
"Templates" subdirectory and collected automatically using this
command to avoid manually listing all instantiations.

It is tempting to use this command to avoid writing the list of source
files for a library or executable target.  While this seems to work,
there is no way for CMake to generate a build system that knows when a
new source file has been added.  Normally the generated build system
knows when it needs to rerun CMake because the CMakeLists.txt file is
modified to add a new source.  When the source is just added to the
directory without modifying this file, one would have to manually
rerun CMake to generate a build system incorporating the new file.

build_command
-------------

Get a command line to build the current project.
This is mainly intended for internal use by the ``CTest`` module.

 build_command(<variable>
               [CONFIGURATION <config>]
               [TARGET <target>]
               [PROJECT_NAME <projname>] # legacy, causes warning
              )

Sets the given ``<variable>`` to a command-line string of the form::

 <cmake> --build . [--config <config>] [--target <target>] [-- -i]

where ``<cmake>`` is the location of the ``cmake(1)`` command-line
tool, and ``<config>`` and ``<target>`` are the values provided to the
``CONFIGURATION`` and ``TARGET`` options, if any.  The trailing ``-- -i``
option is added for :ref:`Makefile Generators` if policy ``CMP0061``
is not set to ``NEW``.

When invoked, this ``cmake --build`` command line will launch the
underlying build system tool.

 build_command(<cachevariable> <makecommand>)

This second signature is deprecated, but still available for backwards
compatibility.  Use the first signature instead.

It sets the given ``<cachevariable>`` to a command-line string as
above but without the ``--target`` option.
The ``<makecommand>`` is ignored but should be the full path to
devenv, nmake, make or one of the end user build tools
for legacy invocations.

.. note::
 In CMake versions prior to 3.0 this command returned a command
 line that directly invokes the native build tool for the current
 generator.  Their implementation of the ``PROJECT_NAME`` option
 had no useful effects, so CMake now warns on use of the option.

create_test_sourcelist
----------------------

Create a test driver and source list for building test programs.

::

 create_test_sourcelist(sourceListName driverName
                        test1 test2 test3
                        EXTRA_INCLUDE include.h
                        FUNCTION function)

A test driver is a program that links together many small tests into a
single executable.  This is useful when building static executables
with large libraries to shrink the total required size.  The list of
source files needed to build the test driver will be in
``sourceListName``.  ``driverName`` is the name of the test driver program.
The rest of the arguments consist of a list of test source files, can
be semicolon separated.  Each test source file should have a function
in it that is the same name as the file with no extension (foo.cxx
should have int foo(int, char*[]);) ``driverName`` will be able to call
each of the tests by name on the command line.  If ``EXTRA_INCLUDE`` is
specified, then the next argument is included into the generated file.
If ``FUNCTION`` is specified, then the next argument is taken as a
function name that is passed a pointer to ac and av.  This can be used
to add extra command line processing to each test.  The
``CMAKE_TESTDRIVER_BEFORE_TESTMAIN`` cmake variable can be set to
have code that will be placed directly before calling the test main function.
``CMAKE_TESTDRIVER_AFTER_TESTMAIN`` can be set to have code that
will be placed directly after the call to the test main function.

define_property
---------------

Define and document custom properties.

::

 define_property(<GLOBAL | DIRECTORY | TARGET | SOURCE |
                  TEST | VARIABLE | CACHED_VARIABLE>
                  PROPERTY <name> [INHERITED]
                  BRIEF_DOCS <brief-doc> [docs...]
                  FULL_DOCS <full-doc> [docs...])

Define one property in a scope for use with the ``set_property()`` and
``get_property()`` commands.  This is primarily useful to associate
documentation with property names that may be retrieved with the
``get_property()`` command. The first argument determines the kind of
scope in which the property should be used.  It must be one of the
following:

::

 GLOBAL    = associated with the global namespace
 DIRECTORY = associated with one directory
 TARGET    = associated with one target
 SOURCE    = associated with one source file
 TEST      = associated with a test named with add_test
 VARIABLE  = documents a CMake language variable
 CACHED_VARIABLE = documents a CMake cache variable

Note that unlike ``set_property()`` and ``get_property()`` no
actual scope needs to be given; only the kind of scope is important.

The required ``PROPERTY`` option is immediately followed by the name of
the property being defined.

If the ``INHERITED`` option then the ``get_property()`` command will
chain up to the next higher scope when the requested property is not set
in the scope given to the command. ``DIRECTORY`` scope chains to
``GLOBAL``. ``TARGET``, ``SOURCE``, and ``TEST`` chain to ``DIRECTORY``.

The ``BRIEF_DOCS`` and ``FULL_DOCS`` options are followed by strings to be
associated with the property as its brief and full documentation.
Corresponding options to the ``get_property()`` command will retrieve
the documentation.

enable_language
---------------

Enable a language (CXX/C/Fortran/etc)

::

 enable_language(<lang> [OPTIONAL] )

This command enables support for the named language in CMake.  This is
the same as the project command but does not create any of the extra
variables that are created by the project command.  Example languages
are CXX, C, Fortran.

This command must be called in file scope, not in a function call.
Furthermore, it must be called in the highest directory common to all
targets using the named language directly for compiling sources or
indirectly through link dependencies.  It is simplest to enable all
needed languages in the top-level directory of a project.

The ``OPTIONAL`` keyword is a placeholder for future implementation and
does not currently work.

enable_testing
--------------

Enable testing for current directory and below.

::

 enable_testing()

Enables testing for this directory and below.  See also the
``add_test()`` command.  Note that ctest expects to find a test file
in the build directory root.  Therefore, this command should be in the
source directory root.

export
------

Export targets from the build tree for use by outside projects.

::

 export(EXPORT <export-name> [NAMESPACE <namespace>] [FILE <filename>])

Create a file ``<filename>`` that may be included by outside projects to
import targets from the current project's build tree.  This is useful
during cross-compiling to build utility executables that can run on
the host platform in one project and then import them into another
project being compiled for the target platform.  If the ``NAMESPACE``
option is given the ``<namespace>`` string will be prepended to all target
names written to the file.

Target installations are associated with the export ``<export-name>``
using the ``EXPORT`` option of the ``install(TARGETS)`` command.

The file created by this command is specific to the build tree and
should never be installed.  See the ``install(EXPORT)`` command to
export targets from an installation tree.

The properties set on the generated IMPORTED targets will have the
same values as the final values of the input TARGETS.

::

 export(TARGETS [target1 [target2 [...]]] [NAMESPACE <namespace>]
        [APPEND] FILE <filename> [EXPORT_LINK_INTERFACE_LIBRARIES])

This signature is similar to the ``EXPORT`` signature, but targets are listed
explicitly rather than specified as an export-name.  If the APPEND option is
given the generated code will be appended to the file instead of overwriting it.
The EXPORT_LINK_INTERFACE_LIBRARIES keyword, if present, causes the
contents of the properties matching
``(IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?`` to be exported, when
policy CMP0022 is NEW.  If a library target is included in the export
but a target to which it links is not included the behavior is
unspecified.

::

 export(PACKAGE <name>)

Store the current build directory in the CMake user package registry
for package ``<name>``.  The find_package command may consider the
directory while searching for package ``<name>``.  This helps dependent
projects find and use a package from the current project's build tree
without help from the user.  Note that the entry in the package
registry that this command creates works only in conjunction with a
package configuration file (``<name>Config.cmake``) that works with the
build tree. In some cases, for example for packaging and for system
wide installations, it is not desirable to write the user package
registry. If the ``CMAKE_EXPORT_NO_PACKAGE_REGISTRY`` variable
is enabled, the ``export(PACKAGE)`` command will do nothing.

::

 export(TARGETS [target1 [target2 [...]]]  [ANDROID_MK <filename>])

This signature exports cmake built targets to the android ndk build system
by creating an Android.mk file that references the prebuilt targets. The
Android NDK supports the use of prebuilt libraries, both static and shared.
This allows cmake to build the libraries of a project and make them available
to an ndk build system complete with transitive dependencies, include flags
and defines required to use the libraries. The signature takes a list of
targets and puts them in the Android.mk file specified by the ``<filename>``
given. This signature can only be used if policy CMP0022 is NEW for all
targets given. A error will be issued if that policy is set to OLD for one
of the targets.

fltk_wrap_ui
------------

Create FLTK user interfaces Wrappers.

::

 fltk_wrap_ui(resultingLibraryName source1
              source2 ... sourceN )

Produce .h and .cxx files for all the .fl and .fld files listed.  The
resulting .h and .cxx files will be added to a variable named
``resultingLibraryName_FLTK_UI_SRCS`` which should be added to your
library.

get_source_file_property
------------------------

Get a property for a source file.

::

 get_source_file_property(VAR file property)

Get a property from a source file.  The value of the property is
stored in the variable ``VAR``.  If the property is not found, ``VAR``
will be set to "NOTFOUND".  Use ``set_source_files_properties()``
to set property values.  Source file properties usually control how the
file is built. One property that is always there is ``LOCATION``

See also the more general ``get_property()`` command.

get_target_property
-------------------

Get a property from a target.

::

 get_target_property(VAR target property)

Get a property from a target.  The value of the property is stored in
the variable ``VAR``.  If the property is not found, ``VAR`` will be set to
"NOTFOUND".  Use ``set_target_properties()`` to set property values.
Properties are usually used to control how a target is built, but some
query the target instead.  This command can get properties for any
target so far created.  The targets do not need to be in the current
``CMakeLists.txt`` file.

See also the more general ``get_property()`` command.

get_test_property
-----------------

Get a property of the test.

::

 get_test_property(test property VAR)

Get a property from the test.  The value of the property is stored in
the variable ``VAR``.  If the test or property is not found, ``VAR`` will
be set to "NOTFOUND".  For a list of standard properties you can type
``cmake --help-property-list``.

See also the more general ``get_property()`` command.

include_directories
-------------------

Add include directories to the build.

::

 include_directories([AFTER|BEFORE] [SYSTEM] dir1 [dir2 ...])

Add the given directories to those the compiler uses to search for
include files.  Relative paths are interpreted as relative to the
current source directory.

The include directories are added to the ``INCLUDE_DIRECTORIES``
directory property for the current ``CMakeLists`` file.  They are also
added to the ``INCLUDE_DIRECTORIES`` target property for each
target in the current ``CMakeLists`` file.  The target property values
are the ones used by the generators.

By default the directories specified are appended onto the current list of
directories.  This default behavior can be changed by setting
``CMAKE_INCLUDE_DIRECTORIES_BEFORE`` to ``ON``.  By using
``AFTER`` or ``BEFORE`` explicitly, you can select between appending and
prepending, independent of the default.

If the ``SYSTEM`` option is given, the compiler will be told the
directories are meant as system include directories on some platforms.
Signalling this setting might achieve effects such as the compiler
skipping warnings, or these fixed-install system files not being
considered in dependency calculations - see compiler docs.

Arguments to ``include_directories`` may use "generator expressions" with
the syntax "$<...>".  See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

include_external_msproject
--------------------------

Include an external Microsoft project file in a workspace.

::

 include_external_msproject(projectname location
                            [TYPE projectTypeGUID]
                            [GUID projectGUID]
                            [PLATFORM platformName]
                            dep1 dep2 ...)

Includes an external Microsoft project in the generated workspace
file.  Currently does nothing on UNIX.  This will create a target
named [projectname].  This can be used in the ``add_dependencies()``
command to make things depend on the external project.

``TYPE``, ``GUID`` and ``PLATFORM`` are optional parameters that allow one to
specify the type of project, id (GUID) of the project and the name of
the target platform.  This is useful for projects requiring values
other than the default (e.g.  WIX projects).

If the imported project has different configuration names than the
current project, set the ``MAP_IMPORTED_CONFIG_<CONFIG>``
target property to specify the mapping.

include_regular_expression
--------------------------

Set the regular expression used for dependency checking.

::

 include_regular_expression(regex_match [regex_complain])

Set the regular expressions used in dependency checking.  Only files
matching ``regex_match`` will be traced as dependencies.  Only files
matching ``regex_complain`` will generate warnings if they cannot be found
(standard header paths are not searched).  The defaults are:

::

 regex_match    = "^.*$" (match everything)
 regex_complain = "^$" (match empty string only)

install
-------

Specify rules to run at install time.

Introduction
^^^^^^^^^^^^

This command generates installation rules for a project.  Rules
specified by calls to this command within a source directory are
executed in order during installation.  The order across directories
is not defined.

There are multiple signatures for this command.  Some of them define
installation options for files and targets.  Options common to
multiple signatures are covered here but they are valid only for
signatures that specify them.  The common options are:

``DESTINATION``
  Specify the directory on disk to which a file will be installed.
  If a full path (with a leading slash or drive letter) is given
  it is used directly.  If a relative path is given it is interpreted
  relative to the value of the ``CMAKE_INSTALL_PREFIX`` variable.
  The prefix can be relocated at install time using the ``DESTDIR``
  mechanism explained in the ``CMAKE_INSTALL_PREFIX`` variable
  documentation.

``PERMISSIONS``
  Specify permissions for installed files.  Valid permissions are
  ``OWNER_READ``, ``OWNER_WRITE``, ``OWNER_EXECUTE``, ``GROUP_READ``,
  ``GROUP_WRITE``, ``GROUP_EXECUTE``, ``WORLD_READ``, ``WORLD_WRITE``,
  ``WORLD_EXECUTE``, ``SETUID``, and ``SETGID``.  Permissions that do
  not make sense on certain platforms are ignored on those platforms.

``CONFIGURATIONS``
  Specify a list of build configurations for which the install rule
  applies (Debug, Release, etc.).

``COMPONENT``
  Specify an installation component name with which the install rule
  is associated, such as "runtime" or "development".  During
  component-specific installation only install rules associated with
  the given component name will be executed.  During a full installation
  all components are installed unless marked with ``EXCLUDE_FROM_ALL``.
  If ``COMPONENT`` is not provided a default component "Unspecified" is
  created.  The default component name may be controlled with the
  ``CMAKE_INSTALL_DEFAULT_COMPONENT_NAME`` variable.

``EXCLUDE_FROM_ALL``
  Specify that the file is excluded from a full installation and only
  installed as part of a component-specific installation

``RENAME``
  Specify a name for an installed file that may be different from the
  original file.  Renaming is allowed only when a single file is
  installed by the command.

``OPTIONAL``
  Specify that it is not an error if the file to be installed does
  not exist.

Command signatures that install files may print messages during
installation.  Use the ``CMAKE_INSTALL_MESSAGE`` variable
to control which messages are printed.

Installing Targets
^^^^^^^^^^^^^^^^^^

::

 install(TARGETS targets... [EXPORT <export-name>]
         [[ARCHIVE|LIBRARY|RUNTIME|OBJECTS|FRAMEWORK|BUNDLE|
           PRIVATE_HEADER|PUBLIC_HEADER|RESOURCE]
          [DESTINATION <dir>]
          [PERMISSIONS permissions...]
          [CONFIGURATIONS [Debug|Release|...]]
          [COMPONENT <component>]
          [OPTIONAL] [EXCLUDE_FROM_ALL]
          [NAMELINK_ONLY|NAMELINK_SKIP]
         ] [...]
         [INCLUDES DESTINATION [<dir> ...]]
         )

The ``TARGETS`` form specifies rules for installing targets from a
project.  There are six kinds of target files that may be installed:
``ARCHIVE``, ``LIBRARY``, ``RUNTIME``, ``OBJECTS``, ``FRAMEWORK``, and
``BUNDLE``. Executables are treated as ``RUNTIME`` targets, except that
those marked with the ``MACOSX_BUNDLE`` property are treated as ``BUNDLE``
targets on OS X.  Static libraries are treated as ``ARCHIVE`` targets,
except that those marked with the ``FRAMEWORK`` property are treated
as ``FRAMEWORK`` targets on OS X.
Module libraries are always treated as ``LIBRARY`` targets.
For non-DLL platforms shared libraries are treated as ``LIBRARY``
targets, except that those marked with the ``FRAMEWORK`` property are
treated as ``FRAMEWORK`` targets on OS X.  For DLL platforms the DLL
part of a shared library is treated as a ``RUNTIME`` target and the
corresponding import library is treated as an ``ARCHIVE`` target.
All Windows-based systems including Cygwin are DLL platforms. Object
libraries are always treated as ``OBJECTS`` targets.
The ``ARCHIVE``, ``LIBRARY``, ``RUNTIME``, ``OBJECTS``, and ``FRAMEWORK``
arguments change the type of target to which the subsequent properties
apply. If none is given the installation properties apply to all target
types.  If only one is given then only targets of that type will be
installed (which can be used to install just a DLL or just an import
library).

The ``PRIVATE_HEADER``, ``PUBLIC_HEADER``, and ``RESOURCE`` arguments
cause subsequent properties to be applied to installing a ``FRAMEWORK``
shared library target's associated files on non-Apple platforms.  Rules
defined by these arguments are ignored on Apple platforms because the
associated files are installed into the appropriate locations inside
the framework folder.  See documentation of the
``PRIVATE_HEADER``, ``PUBLIC_HEADER``, and
``RESOURCE`` target properties for details.

Either ``NAMELINK_ONLY`` or ``NAMELINK_SKIP`` may be specified as a
``LIBRARY`` option.  On some platforms a versioned shared library
has a symbolic link such as::

 lib<name>.so -> lib<name>.so.1

where ``lib<name>.so.1`` is the soname of the library and ``lib<name>.so``
is a "namelink" allowing linkers to find the library when given
``-l<name>``.  The ``NAMELINK_ONLY`` option causes installation of only the
namelink when a library target is installed.  The ``NAMELINK_SKIP`` option
causes installation of library files other than the namelink when a
library target is installed.  When neither option is given both
portions are installed.  On platforms where versioned shared libraries
do not have namelinks or when a library is not versioned the
``NAMELINK_SKIP`` option installs the library and the ``NAMELINK_ONLY``
option installs nothing.  See the ``VERSION`` and
``SOVERSION`` target properties for details on creating versioned
shared libraries.

The ``INCLUDES DESTINATION`` specifies a list of directories
which will be added to the ``INTERFACE_INCLUDE_DIRECTORIES``
target property of the ``<targets>`` when exported by the
``install(EXPORT)`` command.  If a relative path is
specified, it is treated as relative to the ``$<INSTALL_PREFIX>``.
This is independent of the rest of the argument groups and does
not actually install anything.

One or more groups of properties may be specified in a single call to
the ``TARGETS`` form of this command.  A target may be installed more than
once to different locations.  Consider hypothetical targets ``myExe``,
``mySharedLib``, and ``myStaticLib``.  The code:

 install(TARGETS myExe mySharedLib myStaticLib
         RUNTIME DESTINATION bin
         LIBRARY DESTINATION lib
         ARCHIVE DESTINATION lib/static)
 install(TARGETS mySharedLib DESTINATION /some/full/path)

will install ``myExe`` to ``<prefix>/bin`` and ``myStaticLib`` to
``<prefix>/lib/static``.  On non-DLL platforms ``mySharedLib`` will be
installed to ``<prefix>/lib`` and ``/some/full/path``.  On DLL platforms
the ``mySharedLib`` DLL will be installed to ``<prefix>/bin`` and
``/some/full/path`` and its import library will be installed to
``<prefix>/lib/static`` and ``/some/full/path``.

The ``EXPORT`` option associates the installed target files with an
export called ``<export-name>``.  It must appear before any ``RUNTIME``,
``LIBRARY``, ``ARCHIVE``, or ``OBJECTS`` options.  To actually install the
export file itself, call ``install(EXPORT)``, documented below.

Installing a target with the ``EXCLUDE_FROM_ALL`` target property
set to ``TRUE`` has undefined behavior.

The install destination given to the target install ``DESTINATION`` may
use "generator expressions" with the syntax ``$<...>``.  See the
``cmake-generator-expressions(7)`` manual for available expressions.

Installing Files
^^^^^^^^^^^^^^^^

::

 install(<FILES|PROGRAMS> files... DESTINATION <dir>
         [PERMISSIONS permissions...]
         [CONFIGURATIONS [Debug|Release|...]]
         [COMPONENT <component>]
         [RENAME <name>] [OPTIONAL] [EXCLUDE_FROM_ALL])

The ``FILES`` form specifies rules for installing files for a project.
File names given as relative paths are interpreted with respect to the
current source directory.  Files installed by this form are by default
given permissions ``OWNER_WRITE``, ``OWNER_READ``, ``GROUP_READ``, and
``WORLD_READ`` if no ``PERMISSIONS`` argument is given.

The ``PROGRAMS`` form is identical to the ``FILES`` form except that the
default permissions for the installed file also include ``OWNER_EXECUTE``,
``GROUP_EXECUTE``, and ``WORLD_EXECUTE``.  This form is intended to install
programs that are not targets, such as shell scripts.  Use the ``TARGETS``
form to install targets built within the project.

The list of ``files...`` given to ``FILES`` or ``PROGRAMS`` may use
"generator expressions" with the syntax ``$<...>``.  See the
``cmake-generator-expressions(7)`` manual for available expressions.
However, if any item begins in a generator expression it must evaluate
to a full path.

The install destination given to the files install ``DESTINATION`` may
use "generator expressions" with the syntax ``$<...>``.  See the
``cmake-generator-expressions(7)`` manual for available expressions.

Installing Directories
^^^^^^^^^^^^^^^^^^^^^^

::

 install(DIRECTORY dirs... DESTINATION <dir>
         [FILE_PERMISSIONS permissions...]
         [DIRECTORY_PERMISSIONS permissions...]
         [USE_SOURCE_PERMISSIONS] [OPTIONAL] [MESSAGE_NEVER]
         [CONFIGURATIONS [Debug|Release|...]]
         [COMPONENT <component>] [EXCLUDE_FROM_ALL]
         [FILES_MATCHING]
         [[PATTERN <pattern> | REGEX <regex>]
          [EXCLUDE] [PERMISSIONS permissions...]] [...])

The ``DIRECTORY`` form installs contents of one or more directories to a
given destination.  The directory structure is copied verbatim to the
destination.  The last component of each directory name is appended to
the destination directory but a trailing slash may be used to avoid
this because it leaves the last component empty.  Directory names
given as relative paths are interpreted with respect to the current
source directory.  If no input directory names are given the
destination directory will be created but nothing will be installed
into it.  The ``FILE_PERMISSIONS`` and ``DIRECTORY_PERMISSIONS`` options
specify permissions given to files and directories in the destination.
If ``USE_SOURCE_PERMISSIONS`` is specified and ``FILE_PERMISSIONS`` is not,
file permissions will be copied from the source directory structure.
If no permissions are specified files will be given the default
permissions specified in the ``FILES`` form of the command, and the
directories will be given the default permissions specified in the
``PROGRAMS`` form of the command.

The ``MESSAGE_NEVER`` option disables file installation status output.

Installation of directories may be controlled with fine granularity
using the ``PATTERN`` or ``REGEX`` options.  These "match" options specify a
globbing pattern or regular expression to match directories or files
encountered within input directories.  They may be used to apply
certain options (see below) to a subset of the files and directories
encountered.  The full path to each input file or directory (with
forward slashes) is matched against the expression.  A ``PATTERN`` will
match only complete file names: the portion of the full path matching
the pattern must occur at the end of the file name and be preceded by
a slash.  A ``REGEX`` will match any portion of the full path but it may
use ``/`` and ``$`` to simulate the ``PATTERN`` behavior.  By default all
files and directories are installed whether or not they are matched.
The ``FILES_MATCHING`` option may be given before the first match option
to disable installation of files (but not directories) not matched by
any expression.  For example, the code

 install(DIRECTORY src/ DESTINATION include/myproj
         FILES_MATCHING PATTERN "*.h")

will extract and install header files from a source tree.

Some options may follow a ``PATTERN`` or ``REGEX`` expression and are applied
only to files or directories matching them.  The ``EXCLUDE`` option will
skip the matched file or directory.  The ``PERMISSIONS`` option overrides
the permissions setting for the matched file or directory.  For
example the code

 install(DIRECTORY icons scripts/ DESTINATION share/myproj
         PATTERN "CVS" EXCLUDE
         PATTERN "scripts/*"
         PERMISSIONS OWNER_EXECUTE OWNER_WRITE OWNER_READ
                     GROUP_EXECUTE GROUP_READ)

will install the ``icons`` directory to ``share/myproj/icons`` and the
``scripts`` directory to ``share/myproj``.  The icons will get default
file permissions, the scripts will be given specific permissions, and any
``CVS`` directories will be excluded.

The list of ``dirs...`` given to ``DIRECTORY`` and the install destination
given to the directory install ``DESTINATION`` may use "generator expressions"
with the syntax ``$<...>``.  See the ``cmake-generator-expressions(7)``
manual for available expressions.

Custom Installation Logic
^^^^^^^^^^^^^^^^^^^^^^^^^

::

 install([[SCRIPT <file>] [CODE <code>]]
         [COMPONENT <component>] [EXCLUDE_FROM_ALL] [...])

The ``SCRIPT`` form will invoke the given CMake script files during
installation.  If the script file name is a relative path it will be
interpreted with respect to the current source directory.  The ``CODE``
form will invoke the given CMake code during installation.  Code is
specified as a single argument inside a double-quoted string.  For
example, the code

 install(CODE "MESSAGE(\"Sample install message.\")")

will print a message during installation.

Installing Exports
^^^^^^^^^^^^^^^^^^

::

 install(EXPORT <export-name> DESTINATION <dir>
         [NAMESPACE <namespace>] [[FILE <name>.cmake]|
         [EXPORT_ANDROID_MK <name>.mk]]
         [PERMISSIONS permissions...]
         [CONFIGURATIONS [Debug|Release|...]]
         [EXPORT_LINK_INTERFACE_LIBRARIES]
         [COMPONENT <component>]
         [EXCLUDE_FROM_ALL])

The ``EXPORT`` form generates and installs a CMake file containing code to
import targets from the installation tree into another project.
Target installations are associated with the export ``<export-name>``
using the ``EXPORT`` option of the ``install(TARGETS)`` signature
documented above.  The ``NAMESPACE`` option will prepend ``<namespace>`` to
the target names as they are written to the import file.  By default
the generated file will be called ``<export-name>.cmake`` but the ``FILE``
option may be used to specify a different name.  The value given to
the ``FILE`` option must be a file name with the ``.cmake`` extension.
If a ``CONFIGURATIONS`` option is given then the file will only be installed
when one of the named configurations is installed.  Additionally, the
generated import file will reference only the matching target
configurations.  The ``EXPORT_LINK_INTERFACE_LIBRARIES`` keyword, if
present, causes the contents of the properties matching
``(IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?`` to be exported, when
policy ``CMP0022`` is ``NEW``.  If a ``COMPONENT`` option is
specified that does not match that given to the targets associated with
``<export-name>`` the behavior is undefined.  If a library target is
included in the export but a target to which it links is not included
the behavior is unspecified.

In additon to cmake language files, the ``EXPORT_ANDROID_MK`` option maybe
used to specifiy an export to the android ndk build system.  The Android
NDK supports the use of prebuilt libraries, both static and shared. This
allows cmake to build the libraries of a project and make them available
to an ndk build system complete with transitive dependencies, include flags
and defines required to use the libraries.

The ``EXPORT`` form is useful to help outside projects use targets built
and installed by the current project.  For example, the code

 install(TARGETS myexe EXPORT myproj DESTINATION bin)
 install(EXPORT myproj NAMESPACE mp_ DESTINATION lib/myproj)
 install(EXPORT_ANDROID_MK myexp DESTINATION share/ndk-modules)

will install the executable myexe to ``<prefix>/bin`` and code to import
it in the file ``<prefix>/lib/myproj/myproj.cmake`` and
``<prefix>/lib/share/ndk-modules/Android.mk``.  An outside project
may load this file with the include command and reference the ``myexe``
executable from the installation tree using the imported target name
``mp_myexe`` as if the target were built in its own tree.

.. note::
  This command supercedes the ``install_targets()`` command and
  the ``PRE_INSTALL_SCRIPT`` and ``POST_INSTALL_SCRIPT``
  target properties.  It also replaces the ``FILES`` forms of the
  ``install_files()`` and ``install_programs()`` commands.
  The processing order of these install rules relative to
  those generated by ``install_targets()``,
  ``install_files()``, and ``install_programs()`` commands
  is not defined.

link_directories
----------------

Specify directories in which the linker will look for libraries.

::

 link_directories(directory1 directory2 ...)

Specify the paths in which the linker should search for libraries.
The command will apply only to targets created after it is called.
Relative paths given to this command are interpreted as relative to
the current source directory, see ``CMP0015``.

Note that this command is rarely necessary.  Library locations
returned by ``find_package()`` and ``find_library()`` are
absolute paths. Pass these absolute library file paths directly to the
``target_link_libraries()`` command.  CMake will ensure the linker finds
them.

link_libraries
--------------

Link libraries to all targets added later.

::

 link_libraries([item1 [item2 [...]]]
                [[debug|optimized|general] <item>] ...)

Specify libraries or flags to use when linking any targets created later in
the current directory or below by commands such as ``add_executable()``
or ``add_library()``.  See the ``target_link_libraries()`` command
for meaning of arguments.

.. note::
  The ``target_link_libraries()`` command should be preferred whenever
  possible.  Library dependencies are chained automatically, so directory-wide
  specification of link libraries is rarely needed.

load_cache
----------

Load in the values from another project's CMake cache.

::

 load_cache(pathToCacheFile READ_WITH_PREFIX
            prefix entry1...)

Read the cache and store the requested entries in variables with their
name prefixed with the given prefix.  This only reads the values, and
does not create entries in the local project's cache.

::

 load_cache(pathToCacheFile [EXCLUDE entry1...]
            [INCLUDE_INTERNALS entry1...])

Load in the values from another cache and store them in the local
project's cache as internal entries.  This is useful for a project
that depends on another project built in a different tree.  ``EXCLUDE``
option can be used to provide a list of entries to be excluded.
``INCLUDE_INTERNALS`` can be used to provide a list of internal entries to
be included.  Normally, no internal entries are brought in.  Use of
this form of the command is strongly discouraged, but it is provided
for backward compatibility.

project
-------

Set a name, version, and enable languages for the entire project.

 project(<PROJECT-NAME> [LANGUAGES] [<language-name>...])
 project(<PROJECT-NAME>
         [VERSION <major>[.<minor>[.<patch>[.<tweak>]]]]
         [DESCRIPTION <project-description-string>]
         [LANGUAGES <language-name>...])

Sets the name of the project and stores the name in the
``PROJECT_NAME`` variable.  Additionally this sets variables

* ``PROJECT_SOURCE_DIR``,
  ``<PROJECT-NAME>_SOURCE_DIR``
* ``PROJECT_BINARY_DIR``,
  ``<PROJECT-NAME>_BINARY_DIR``

If ``VERSION`` is specified, given components must be non-negative integers.
If ``VERSION`` is not specified, the default version is the empty string.
The ``VERSION`` option may not be used unless policy ``CMP0048`` is
set to ``NEW``.

The ``project()`` command stores the version number and its components
in variables

* ``PROJECT_VERSION``,
  ``<PROJECT-NAME>_VERSION``
* ``PROJECT_VERSION_MAJOR``,
  ``<PROJECT-NAME>_VERSION_MAJOR``
* ``PROJECT_VERSION_MINOR``,
  ``<PROJECT-NAME>_VERSION_MINOR``
* ``PROJECT_VERSION_PATCH``,
  ``<PROJECT-NAME>_VERSION_PATCH``
* ``PROJECT_VERSION_TWEAK``,
  ``<PROJECT-NAME>_VERSION_TWEAK``

Variables corresponding to unspecified versions are set to the empty string
(if policy ``CMP0048`` is set to ``NEW``).

If optional ``DESCRIPTION`` is given, then additional ``PROJECT_DESCRIPTION``
variable will be set to its argument. The argument must be a string with short
description of the project (only a few words).

Optionally you can specify which languages your project supports.
Example languages are ``C``, ``CXX`` (i.e.  C++), ``Fortran``, etc.
By default ``C`` and ``CXX`` are enabled if no language options are
given.  Specify language ``NONE``, or use the ``LANGUAGES`` keyword
and list no languages, to skip enabling any languages.

If a variable exists called ``CMAKE_PROJECT_<PROJECT-NAME>_INCLUDE``,
the file pointed to by that variable will be included as the last step of the
project command.

The top-level ``CMakeLists.txt`` file for a project must contain a
literal, direct call to the ``project()`` command; loading one
through the ``include()`` command is not sufficient.  If no such
call exists CMake will implicitly add one to the top that enables the
default languages (``C`` and ``CXX``).

.. note::
  Call the ``cmake_minimum_required()`` command at the beginning
  of the top-level ``CMakeLists.txt`` file even before calling the
  ``project()`` command.  It is important to establish version and
  policy settings before invoking other commands whose behavior they
  may affect.  See also policy ``CMP0000``.

qt_wrap_cpp
-----------

Create Qt Wrappers.

::

 qt_wrap_cpp(resultingLibraryName DestName
             SourceLists ...)

Produce moc files for all the .h files listed in the SourceLists.  The
moc files will be added to the library using the ``DestName`` source list.

qt_wrap_ui
----------

Create Qt user interfaces Wrappers.

::

 qt_wrap_ui(resultingLibraryName HeadersDestName
            SourcesDestName SourceLists ...)

Produce .h and .cxx files for all the .ui files listed in the
``SourceLists``.  The .h files will be added to the library using the
``HeadersDestNamesource`` list.  The .cxx files will be added to the
library using the ``SourcesDestNamesource`` list.

remove_definitions
------------------

Removes -D define flags added by ``add_definitions()``.

::

 remove_definitions(-DFOO -DBAR ...)

Removes flags (added by ``add_definitions()``) from the compiler
command line for sources in the current directory and below.

set_source_files_properties
---------------------------

Source files can have properties that affect how they are built.

::

 set_source_files_properties([file1 [file2 [...]]]
                             PROPERTIES prop1 value1
                             [prop2 value2 [...]])

Set properties associated with source files using a key/value paired
list.  See :ref:`Source File Properties` for the list of properties known
to CMake.  Source file properties are visible only to targets added
in the same directory (CMakeLists.txt).

set_target_properties
---------------------

Targets can have properties that affect how they are built.

::

 set_target_properties(target1 target2 ...
                       PROPERTIES prop1 value1
                       prop2 value2 ...)

Set properties on a target.  The syntax for the command is to list all
the files you want to change, and then provide the values you want to
set next.  You can use any prop value pair you want and extract it
later with the ``get_property()`` or ``get_target_property()``
command.

See :ref:`Target Properties` for the list of properties known to CMake.

set_tests_properties
--------------------

Set a property of the tests.

::

 set_tests_properties(test1 [test2...] PROPERTIES prop1 value1 prop2 value2)

Set a property for the tests.  If the test is not found, CMake
will report an error.
``Generator expressions`` will be
expanded the same as supported by the test's ``add_test()`` call.  See
:ref:`Test Properties` for the list of properties known to CMake.

source_group
------------

Define a grouping for source files in IDE project generation.
There are two different signatures to create source groups.

::

 source_group(<name> [FILES <src>...] [REGULAR_EXPRESSION <regex>])
 source_group(TREE <root> [PREFIX <prefix>] [FILES <src>...])

Defines a group into which sources will be placed in project files.
This is intended to set up file tabs in Visual Studio.
The options are:

``TREE``
 CMake will automatically detect, from ``<src>`` files paths, source groups
 it needs to create, to keep structure of source groups analogically to the
 actual files and directories structure in the project. Paths of ``<src>``
 files will be cut to be relative to ``<root>``.

``PREFIX``
 Source group and files located directly in ``<root>`` path, will be placed
 in ``<prefix>`` source groups.

``FILES``
 Any source file specified explicitly will be placed in group
 ``<name>``.  Relative paths are interpreted with respect to the
 current source directory.

``REGULAR_EXPRESSION``
 Any source file whose name matches the regular expression will
 be placed in group ``<name>``.

If a source file matches multiple groups, the *last* group that
explicitly lists the file with ``FILES`` will be favored, if any.
If no group explicitly lists the file, the *last* group whose
regular expression matches the file will be favored.

The ``<name>`` of the group and ``<prefix>`` argument may contain backslashes
to specify subgroups:

 source_group(outer\\inner ...)
 source_group(TREE <root> PREFIX sources\\inc ...)

For backwards compatibility, the short-hand signature

 source_group(<name> <regex>)

is equivalent to

 source_group(<name> REGULAR_EXPRESSION <regex>)

target_compile_definitions
--------------------------

Add compile definitions to a target.

::

 target_compile_definitions(<target>
   <INTERFACE|PUBLIC|PRIVATE> [items1...]
   [<INTERFACE|PUBLIC|PRIVATE> [items2...] ...])

Specify compile definitions to use when compiling a given ``<target>``.  The
named ``<target>`` must have been created by a command such as
``add_executable()`` or ``add_library()`` and must not be an
:ref:`Imported Target <Imported Targets>`.

The ``INTERFACE``, ``PUBLIC`` and ``PRIVATE`` keywords are required to
specify the scope of the following arguments.  ``PRIVATE`` and ``PUBLIC``
items will populate the ``COMPILE_DEFINITIONS`` property of
``<target>``. ``PUBLIC`` and ``INTERFACE`` items will populate the
``INTERFACE_COMPILE_DEFINITIONS`` property of ``<target>``.  The
following arguments specify compile definitions.  Repeated calls for the
same ``<target>`` append items in the order called.

Arguments to ``target_compile_definitions`` may use "generator expressions"
with the syntax ``$<...>``.  See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

target_compile_features
-----------------------

Add expected compiler features to a target.

::

 target_compile_features(<target> <PRIVATE|PUBLIC|INTERFACE> <feature> [...])

Specify compiler features required when compiling a given target.  If the
feature is not listed in the ``CMAKE_C_COMPILE_FEATURES`` variable
or ``CMAKE_CXX_COMPILE_FEATURES`` variable,
then an error will be reported by CMake.  If the use of the feature requires
an additional compiler flag, such as ``-std=gnu++11``, the flag will be added
automatically.

The ``INTERFACE``, ``PUBLIC`` and ``PRIVATE`` keywords are required to
specify the scope of the features.  ``PRIVATE`` and ``PUBLIC`` items will
populate the ``COMPILE_FEATURES`` property of ``<target>``.
``PUBLIC`` and ``INTERFACE`` items will populate the
``INTERFACE_COMPILE_FEATURES`` property of ``<target>``.  Repeated
calls for the same ``<target>`` append items.

The named ``<target>`` must have been created by a command such as
``add_executable()`` or ``add_library()`` and must not be
an ``IMPORTED`` target.

Arguments to ``target_compile_features`` may use "generator expressions"
with the syntax ``$<...>``.
See the ``cmake-generator-expressions(7)`` manual for available
expressions.  See the ``cmake-compile-features(7)`` manual for
information on compile features and a list of supported compilers.

target_compile_options
----------------------

Add compile options to a target.

::

 target_compile_options(<target> [BEFORE]
   <INTERFACE|PUBLIC|PRIVATE> [items1...]
   [<INTERFACE|PUBLIC|PRIVATE> [items2...] ...])

Specify compile options to use when compiling a given target.  The
named ``<target>`` must have been created by a command such as
``add_executable()`` or ``add_library()`` and must not be an
:ref:`IMPORTED Target <Imported Targets>`.  If ``BEFORE`` is specified,
the content will be prepended to the property instead of being appended.

This command can be used to add any options, but
alternative commands exist to add preprocessor definitions
(``target_compile_definitions()`` and ``add_definitions()``) or
include directories (``target_include_directories()`` and
``include_directories()``).  See documentation of the
``directory`` and
``target`` ``COMPILE_OPTIONS`` properties.

The ``INTERFACE``, ``PUBLIC`` and ``PRIVATE`` keywords are required to
specify the scope of the following arguments.  ``PRIVATE`` and ``PUBLIC``
items will populate the ``COMPILE_OPTIONS`` property of
``<target>``.  ``PUBLIC`` and ``INTERFACE`` items will populate the
``INTERFACE_COMPILE_OPTIONS`` property of ``<target>``.  The
following arguments specify compile options.  Repeated calls for the same
``<target>`` append items in the order called.

Arguments to ``target_compile_options`` may use "generator expressions"
with the syntax ``$<...>``. See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

target_include_directories
--------------------------

Add include directories to a target.

::

 target_include_directories(<target> [SYSTEM] [BEFORE]
   <INTERFACE|PUBLIC|PRIVATE> [items1...]
   [<INTERFACE|PUBLIC|PRIVATE> [items2...] ...])

Specify include directories to use when compiling a given target.
The named ``<target>`` must have been created by a command such
as ``add_executable()`` or ``add_library()`` and must not be an
``IMPORTED`` target.

If ``BEFORE`` is specified, the content will be prepended to the property
instead of being appended.

The ``INTERFACE``, ``PUBLIC`` and ``PRIVATE`` keywords are required to specify
the scope of the following arguments.  ``PRIVATE`` and ``PUBLIC`` items will
populate the ``INCLUDE_DIRECTORIES`` property of ``<target>``.
``PUBLIC`` and ``INTERFACE`` items will populate the
``INTERFACE_INCLUDE_DIRECTORIES``
property of ``<target>``.  The following arguments specify include
directories.

Specified include directories may be absolute paths or relative paths.
Repeated calls for the same <target> append items in the order called.  If
``SYSTEM`` is specified, the compiler will be told the
directories are meant as system include directories on some platforms
(signalling this setting might achieve effects such as the compiler
skipping warnings, or these fixed-install system files not being
considered in dependency calculations - see compiler docs).  If ``SYSTEM``
is used together with ``PUBLIC`` or ``INTERFACE``, the
``INTERFACE_SYSTEM_INCLUDE_DIRECTORIES`` target property will be
populated with the specified directories.

Arguments to ``target_include_directories`` may use "generator expressions"
with the syntax ``$<...>``.  See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

Include directories usage requirements commonly differ between the build-tree
and the install-tree.  The ``BUILD_INTERFACE`` and ``INSTALL_INTERFACE``
generator expressions can be used to describe separate usage requirements
based on the usage location.  Relative paths are allowed within the
``INSTALL_INTERFACE`` expression and are interpreted relative to the
installation prefix.  For example:

 target_include_directories(mylib PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include/mylib>
   $<INSTALL_INTERFACE:include/mylib>  # <prefix>/include/mylib
 )

Creating Relocatable Packages
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Note that it is not advisable to populate the ``INSTALL_INTERFACE`` of the
``INTERFACE_INCLUDE_DIRECTORIES`` of a target with absolute paths to the include
directories of dependencies.  That would hard-code into installed packages
the include directory paths for dependencies
**as found on the machine the package was made on**.

The ``INSTALL_INTERFACE`` of the ``INTERFACE_INCLUDE_DIRECTORIES`` is only
suitable for specifying the required include directories for headers
provided with the target itself, not those provided by the transitive
dependencies listed in its ``INTERFACE_LINK_LIBRARIES`` target
property.  Those dependencies should themselves be targets that specify
their own header locations in ``INTERFACE_INCLUDE_DIRECTORIES``.

See the :ref:`Creating Relocatable Packages` section of the
``cmake-packages(7)`` manual for discussion of additional care
that must be taken when specifying usage requirements while creating
packages for redistribution.

target_link_libraries
---------------------

Specify libraries or flags to use when linking a given target and/or
its dependents.  :ref:`Usage requirements <Target Usage Requirements>`
from linked library targets will be propagated.  Usage requirements
of a target's dependencies affect compilation of its own sources.

Overview
^^^^^^^^

This command has several signatures as detailed in subsections below.
All of them have the general form::

 target_link_libraries(<target> ... <item>... ...)

The named ``<target>`` must have been created in the current directory by
a command such as ``add_executable()`` or ``add_library()``.
Repeated calls for the same ``<target>`` append items in the order called.
Each ``<item>`` may be:

* **A library target name**: The generated link line will have the
  full path to the linkable library file associated with the target.
  The buildsystem will have a dependency to re-link ``<target>`` if
  the library file changes.

  The named target must be created by ``add_library()`` within
  the project or as an :ref:`IMPORTED library <Imported Targets>`.
  If it is created within the project an ordering dependency will
  automatically be added in the build system to make sure the named
  library target is up-to-date before the ``<target>`` links.

  If an imported library has the ``IMPORTED_NO_SONAME``
  target property set, CMake may ask the linker to search for
  the library instead of using the full path
  (e.g. ``/usr/lib/libfoo.so`` becomes ``-lfoo``).

* **A full path to a library file**: The generated link line will
  normally preserve the full path to the file. The buildsystem will
  have a dependency to re-link ``<target>`` if the library file changes.

  There are some cases where CMake may ask the linker to search for
  the library (e.g. ``/usr/lib/libfoo.so`` becomes ``-lfoo``), such
  as when a shared library is detected to have no ``SONAME`` field.
  See policy ``CMP0060`` for discussion of another case.

  If the library file is in a Mac OSX framework, the ``Headers`` directory
  of the framework will also be processed as a
  :ref:`usage requirement <Target Usage Requirements>`.  This has the same
  effect as passing the framework directory as an include directory.

  On :ref:`Visual Studio Generators` for VS 2010 and above, library files
  ending in ``.targets`` will be treated as MSBuild targets files and
  imported into generated project files.  This is not supported by other
  generators.

* **A plain library name**: The generated link line will ask the linker
  to search for the library (e.g. ``foo`` becomes ``-lfoo`` or ``foo.lib``).

* **A link flag**: Item names starting with ``-``, but not ``-l`` or
  ``-framework``, are treated as linker flags.  Note that such flags will
  be treated like any other library link item for purposes of transitive
  dependencies, so they are generally safe to specify only as private link
  items that will not propagate to dependents.

  Link flags specified here are inserted into the link command in the same
  place as the link libraries. This might not be correct, depending on
  the linker. Use the ``LINK_FLAGS`` target property to add link
  flags explicitly. The flags will then be placed at the toolchain-defined
  flag position in the link command.

* A ``debug``, ``optimized``, or ``general`` keyword immediately followed
  by another ``<item>``.  The item following such a keyword will be used
  only for the corresponding build configuration.  The ``debug`` keyword
  corresponds to the ``Debug`` configuration (or to configurations named
  in the ``DEBUG_CONFIGURATIONS`` global property if it is set).
  The ``optimized`` keyword corresponds to all other configurations.  The
  ``general`` keyword corresponds to all configurations, and is purely
  optional.  Higher granularity may be achieved for per-configuration
  rules by creating and linking to
  :ref:`IMPORTED library targets <Imported Targets>`.

Items containing ``::``, such as ``Foo::Bar``, are assumed to be
:ref:`IMPORTED <Imported Targets>` or :ref:`ALIAS <Alias Targets>` library
target names and will cause an error if no such target exists.
See policy ``CMP0028``.

Arguments to ``target_link_libraries`` may use "generator expressions"
with the syntax ``$<...>``.  Note however, that generator expressions
will not be used in OLD handling of ``CMP0003`` or ``CMP0004``.
See the ``cmake-generator-expressions(7)`` manual for available
expressions.  See the ``cmake-buildsystem(7)`` manual for more on
defining buildsystem properties.

Libraries for a Target and/or its Dependents
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 target_link_libraries(<target>
                       <PRIVATE|PUBLIC|INTERFACE> <item>...
                      [<PRIVATE|PUBLIC|INTERFACE> <item>...]...)

The ``PUBLIC``, ``PRIVATE`` and ``INTERFACE`` keywords can be used to
specify both the link dependencies and the link interface in one command.
Libraries and targets following ``PUBLIC`` are linked to, and are made
part of the link interface.  Libraries and targets following ``PRIVATE``
are linked to, but are not made part of the link interface.  Libraries
following ``INTERFACE`` are appended to the link interface and are not
used for linking ``<target>``.

Libraries for both a Target and its Dependents
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 target_link_libraries(<target> <item>...)

Library dependencies are transitive by default with this signature.
When this target is linked into another target then the libraries
linked to this target will appear on the link line for the other
target too.  This transitive "link interface" is stored in the
``INTERFACE_LINK_LIBRARIES`` target property and may be overridden
by setting the property directly.  When ``CMP0022`` is not set to
``NEW``, transitive linking is built in but may be overridden by the
``LINK_INTERFACE_LIBRARIES`` property.  Calls to other signatures
of this command may set the property making any libraries linked
exclusively by this signature private.

Libraries for a Target and/or its Dependents (Legacy)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 target_link_libraries(<target>
                       <LINK_PRIVATE|LINK_PUBLIC> <lib>...
                      [<LINK_PRIVATE|LINK_PUBLIC> <lib>...]...)

The ``LINK_PUBLIC`` and ``LINK_PRIVATE`` modes can be used to specify both
the link dependencies and the link interface in one command.

This signature is for compatibility only.  Prefer the ``PUBLIC`` or
``PRIVATE`` keywords instead.

Libraries and targets following ``LINK_PUBLIC`` are linked to, and are
made part of the ``INTERFACE_LINK_LIBRARIES``.  If policy
``CMP0022`` is not ``NEW``, they are also made part of the
``LINK_INTERFACE_LIBRARIES``.  Libraries and targets following
``LINK_PRIVATE`` are linked to, but are not made part of the
``INTERFACE_LINK_LIBRARIES`` (or ``LINK_INTERFACE_LIBRARIES``).

Libraries for Dependents Only (Legacy)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 target_link_libraries(<target> LINK_INTERFACE_LIBRARIES <item>...)

The ``LINK_INTERFACE_LIBRARIES`` mode appends the libraries to the
``INTERFACE_LINK_LIBRARIES`` target property instead of using them
for linking.  If policy ``CMP0022`` is not ``NEW``, then this mode
also appends libraries to the ``LINK_INTERFACE_LIBRARIES`` and its
per-configuration equivalent.

This signature is for compatibility only.  Prefer the ``INTERFACE`` mode
instead.

Libraries specified as ``debug`` are wrapped in a generator expression to
correspond to debug builds.  If policy ``CMP0022`` is
not ``NEW``, the libraries are also appended to the
``LINK_INTERFACE_LIBRARIES_DEBUG``
property (or to the properties corresponding to configurations listed in
the ``DEBUG_CONFIGURATIONS`` global property if it is set).
Libraries specified as ``optimized`` are appended to the
``INTERFACE_LINK_LIBRARIES`` property.  If policy ``CMP0022``
is not ``NEW``, they are also appended to the
``LINK_INTERFACE_LIBRARIES`` property.  Libraries specified as
``general`` (or without any keyword) are treated as if specified for both
``debug`` and ``optimized``.

Cyclic Dependencies of Static Libraries
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The library dependency graph is normally acyclic (a DAG), but in the case
of mutually-dependent ``STATIC`` libraries CMake allows the graph to
contain cycles (strongly connected components).  When another target links
to one of the libraries, CMake repeats the entire connected component.
For example, the code

 add_library(A STATIC a.c)
 add_library(B STATIC b.c)
 target_link_libraries(A B)
 target_link_libraries(B A)
 add_executable(main main.c)
 target_link_libraries(main A)

links ``main`` to ``A B A B``.  While one repetition is usually
sufficient, pathological object file and symbol arrangements can require
more.  One may handle such cases by using the
``LINK_INTERFACE_MULTIPLICITY`` target property or by manually
repeating the component in the last ``target_link_libraries`` call.
However, if two archives are really so interdependent they should probably
be combined into a single archive, perhaps by using :ref:`Object Libraries`.

Creating Relocatable Packages
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Note that it is not advisable to populate the
``INTERFACE_LINK_LIBRARIES`` of a target with absolute paths to dependencies.
That would hard-code into installed packages the library file paths
for dependencies **as found on the machine the package was made on**.

See the :ref:`Creating Relocatable Packages` section of the
``cmake-packages(7)`` manual for discussion of additional care
that must be taken when specifying usage requirements while creating
packages for redistribution.

target_sources
--------------

Add sources to a target.

::

 target_sources(<target>
   <INTERFACE|PUBLIC|PRIVATE> [items1...]
   [<INTERFACE|PUBLIC|PRIVATE> [items2...] ...])

Specify sources to use when compiling a given target.  The
named ``<target>`` must have been created by a command such as
``add_executable()`` or ``add_library()`` and must not be an
:ref:`IMPORTED Target <Imported Targets>`.

The ``INTERFACE``, ``PUBLIC`` and ``PRIVATE`` keywords are required to
specify the scope of the following arguments.  ``PRIVATE`` and ``PUBLIC``
items will populate the ``SOURCES`` property of
``<target>``.  ``PUBLIC`` and ``INTERFACE`` items will populate the
``INTERFACE_SOURCES`` property of ``<target>``.  The
following arguments specify sources.  Repeated calls for the same
``<target>`` append items in the order called.

Arguments to ``target_sources`` may use "generator expressions"
with the syntax ``$<...>``. See the ``cmake-generator-expressions(7)``
manual for available expressions.  See the ``cmake-buildsystem(7)``
manual for more on defining buildsystem properties.

try_compile
-----------

Try building some code.

Try Compiling Whole Projects
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 try_compile(RESULT_VAR <bindir> <srcdir>
             <projectName> [<targetName>] [CMAKE_FLAGS <flags>...]
             [OUTPUT_VARIABLE <var>])

Try building a project.  The success or failure of the ``try_compile``,
i.e. ``TRUE`` or ``FALSE`` respectively, is returned in ``RESULT_VAR``.

In this form, ``<srcdir>`` should contain a complete CMake project with a
``CMakeLists.txt`` file and all sources.  The ``<bindir>`` and ``<srcdir>``
will not be deleted after this command is run.  Specify ``<targetName>`` to
build a specific target instead of the ``all`` or ``ALL_BUILD`` target.  See
below for the meaning of other options.

Try Compiling Source Files
^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 try_compile(RESULT_VAR <bindir> <srcfile|SOURCES srcfile...>
             [CMAKE_FLAGS <flags>...]
             [COMPILE_DEFINITIONS <defs>...]
             [LINK_LIBRARIES <libs>...]
             [OUTPUT_VARIABLE <var>]
             [COPY_FILE <fileName> [COPY_FILE_ERROR <var>]]
             [<LANG>_STANDARD <std>]
             [<LANG>_STANDARD_REQUIRED <bool>]
             [<LANG>_EXTENSIONS <bool>]
             )

Try building an executable from one or more source files.  The success or
failure of the ``try_compile``, i.e. ``TRUE`` or ``FALSE`` respectively, is
returned in ``RESULT_VAR``.

In this form the user need only supply one or more source files that include a
definition for ``main``.  CMake will create a ``CMakeLists.txt`` file to build
the source(s) as an executable that looks something like this::

 add_definitions(<expanded COMPILE_DEFINITIONS from caller>)
 include_directories(${INCLUDE_DIRECTORIES})
 link_directories(${LINK_DIRECTORIES})
 add_executable(cmTryCompileExec <srcfile>...)
 target_link_libraries(cmTryCompileExec ${LINK_LIBRARIES})

The options are:

``CMAKE_FLAGS <flags>...``
  Specify flags of the form ``-DVAR:TYPE=VALUE`` to be passed to
  the ``cmake`` command-line used to drive the test build.
  The above example shows how values for variables
  ``INCLUDE_DIRECTORIES``, ``LINK_DIRECTORIES``, and ``LINK_LIBRARIES``
  are used.

``COMPILE_DEFINITIONS <defs>...``
  Specify ``-Ddefinition`` arguments to pass to ``add_definitions``
  in the generated test project.

``COPY_FILE <fileName>``
  Copy the linked executable to the given ``<fileName>``.

``COPY_FILE_ERROR <var>``
  Use after ``COPY_FILE`` to capture into variable ``<var>`` any error
  message encountered while trying to copy the file.

``LINK_LIBRARIES <libs>...``
  Specify libraries to be linked in the generated project.
  The list of libraries may refer to system libraries and to
  :ref:`Imported Targets <Imported Targets>` from the calling project.

  If this option is specified, any ``-DLINK_LIBRARIES=...`` value
  given to the ``CMAKE_FLAGS`` option will be ignored.

``OUTPUT_VARIABLE <var>``
  Store the output from the build process the given variable.

``<LANG>_STANDARD <std>``
  Specify the ``C_STANDARD``, ``CXX_STANDARD``,
  or ``CUDA_STANDARD`` target property of the generated project.

``<LANG>_STANDARD_REQUIRED <bool>``
  Specify the ``C_STANDARD_REQUIRED``,
  ``CXX_STANDARD_REQUIRED``, or ``CUDA_STANDARD_REQUIRED``
  target property of the generated project.

``<LANG>_EXTENSIONS <bool>``
  Specify the ``C_EXTENSIONS``, ``CXX_EXTENSIONS``,
  or ``CUDA_EXTENSIONS`` target property of the generated project.

In this version all files in ``<bindir>/CMakeFiles/CMakeTmp`` will be
cleaned automatically.  For debugging, ``--debug-trycompile`` can be
passed to ``cmake`` to avoid this clean.  However, multiple sequential
``try_compile`` operations reuse this single output directory.  If you use
``--debug-trycompile``, you can only debug one ``try_compile`` call at a time.
The recommended procedure is to protect all ``try_compile`` calls in your
project by ``if(NOT DEFINED RESULT_VAR)`` logic, configure with cmake
all the way through once, then delete the cache entry associated with
the try_compile call of interest, and then re-run cmake again with
``--debug-trycompile``.

Other Behavior Settings
^^^^^^^^^^^^^^^^^^^^^^^

If set, the following variables are passed in to the generated
try_compile CMakeLists.txt to initialize compile target properties with
default values:

* ``CMAKE_ENABLE_EXPORTS``
* ``CMAKE_LINK_SEARCH_START_STATIC``
* ``CMAKE_LINK_SEARCH_END_STATIC``
* ``CMAKE_POSITION_INDEPENDENT_CODE``

If ``CMP0056`` is set to ``NEW``, then
``CMAKE_EXE_LINKER_FLAGS`` is passed in as well.

The current setting of ``CMP0065`` is set in the generated project.

Set the ``CMAKE_TRY_COMPILE_CONFIGURATION`` variable to choose
a build configuration.

Set the ``CMAKE_TRY_COMPILE_TARGET_TYPE`` variable to specify
the type of target used for the source file signature.

Set the ``CMAKE_TRY_COMPILE_PLATFORM_VARIABLES`` variable to specify
variables that must be propagated into the test project.  This variable is
meant for use only in toolchain files.

If ``CMP0067`` is set to ``NEW``, or any of the ``<LANG>_STANDARD``,
``<LANG>_STANDARD_REQUIRED``, or ``<LANG>_EXTENSIONS`` options are used,
then the language standard variables are honored:

* ``CMAKE_C_STANDARD``
* ``CMAKE_C_STANDARD_REQUIRED``
* ``CMAKE_C_EXTENSIONS``
* ``CMAKE_CXX_STANDARD``
* ``CMAKE_CXX_STANDARD_REQUIRED``
* ``CMAKE_CXX_EXTENSIONS``
* ``CMAKE_CUDA_STANDARD``
* ``CMAKE_CUDA_STANDARD_REQUIRED``
* ``CMAKE_CUDA_EXTENSIONS``

Their values are used to set the corresponding target properties in
the generated project (unless overridden by an explicit option).

try_run
-------

Try compiling and then running some code.

Try Compiling and Running Source Files
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 try_run(RUN_RESULT_VAR COMPILE_RESULT_VAR
         bindir srcfile [CMAKE_FLAGS <flags>...]
         [COMPILE_DEFINITIONS <defs>...]
         [LINK_LIBRARIES <libs>...]
         [COMPILE_OUTPUT_VARIABLE <var>]
         [RUN_OUTPUT_VARIABLE <var>]
         [OUTPUT_VARIABLE <var>]
         [ARGS <args>...])

Try compiling a ``<srcfile>``.  Returns ``TRUE`` or ``FALSE`` for success
or failure in ``COMPILE_RESULT_VAR``.  If the compile succeeded, runs the
executable and returns its exit code in ``RUN_RESULT_VAR``.  If the
executable was built, but failed to run, then ``RUN_RESULT_VAR`` will be
set to ``FAILED_TO_RUN``.  See the ``try_compile()`` command for
information on how the test project is constructed to build the source file.

The options are:

``CMAKE_FLAGS <flags>...``
  Specify flags of the form ``-DVAR:TYPE=VALUE`` to be passed to
  the ``cmake`` command-line used to drive the test build.
  The example in ``try_compile()`` shows how values for variables
  ``INCLUDE_DIRECTORIES``, ``LINK_DIRECTORIES``, and ``LINK_LIBRARIES``
  are used.

``COMPILE_DEFINITIONS <defs>...``
  Specify ``-Ddefinition`` arguments to pass to ``add_definitions``
  in the generated test project.

``COMPILE_OUTPUT_VARIABLE <var>``
  Report the compile step build output in a given variable.

``LINK_LIBRARIES <libs>...``
  Specify libraries to be linked in the generated project.
  The list of libraries may refer to system libraries and to
  :ref:`Imported Targets <Imported Targets>` from the calling project.

  If this option is specified, any ``-DLINK_LIBRARIES=...`` value
  given to the ``CMAKE_FLAGS`` option will be ignored.

``OUTPUT_VARIABLE <var>``
  Report the compile build output and the output from running the executable
  in the given variable.  This option exists for legacy reasons.  Prefer
  ``COMPILE_OUTPUT_VARIABLE`` and ``RUN_OUTPUT_VARIABLE`` instead.

``RUN_OUTPUT_VARIABLE <var>``
  Report the output from running the executable in a given variable.

Other Behavior Settings
^^^^^^^^^^^^^^^^^^^^^^^

Set the ``CMAKE_TRY_COMPILE_CONFIGURATION`` variable to choose
a build configuration.

Behavior when Cross Compiling
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When cross compiling, the executable compiled in the first step
usually cannot be run on the build host.  The ``try_run`` command checks
the ``CMAKE_CROSSCOMPILING`` variable to detect whether CMake is in
cross-compiling mode.  If that is the case, it will still try to compile
the executable, but it will not try to run the executable unless the
``CMAKE_CROSSCOMPILING_EMULATOR`` variable is set.  Instead it
will create cache variables which must be filled by the user or by
presetting them in some CMake script file to the values the executable
would have produced if it had been run on its actual target platform.
These cache entries are:

``<RUN_RESULT_VAR>``
  Exit code if the executable were to be run on the target platform.

``<RUN_RESULT_VAR>__TRYRUN_OUTPUT``
  Output from stdout and stderr if the executable were to be run on
  the target platform.  This is created only if the
  ``RUN_OUTPUT_VARIABLE`` or ``OUTPUT_VARIABLE`` option was used.

In order to make cross compiling your project easier, use ``try_run``
only if really required.  If you use ``try_run``, use the
``RUN_OUTPUT_VARIABLE`` or ``OUTPUT_VARIABLE`` options only if really
required.  Using them will require that when cross-compiling, the cache
variables will have to be set manually to the output of the executable.
You can also "guard" the calls to ``try_run`` with an ``if()``
block checking the ``CMAKE_CROSSCOMPILING`` variable and
provide an easy-to-preset alternative for this case.

CTest Commands
==============

These commands are available only in CTest scripts.

ctest_build
-----------

Perform the :ref:`CTest Build Step` as a :ref:`Dashboard Client`.

::

 ctest_build([BUILD <build-dir>] [APPEND]
             [CONFIGURATION <config>]
             [FLAGS <flags>]
             [PROJECT_NAME <project-name>]
             [TARGET <target-name>]
             [NUMBER_ERRORS <num-err-var>]
             [NUMBER_WARNINGS <num-warn-var>]
             [RETURN_VALUE <result-var>]
             [CAPTURE_CMAKE_ERROR <result-var>]
             )

Build the project and store results in ``Build.xml``
for submission with the ``ctest_submit()`` command.

The ``CTEST_BUILD_COMMAND`` variable may be set to explicitly
specify the build command line.  Otherwise the build command line is
computed automatically based on the options given.

The options are:

``BUILD <build-dir>``
  Specify the top-level build directory.  If not given, the
  ``CTEST_BINARY_DIRECTORY`` variable is used.

``APPEND``
  Mark ``Build.xml`` for append to results previously submitted to a
  dashboard server since the last ``ctest_start()`` call.
  Append semantics are defined by the dashboard server in use.
  This does *not* cause results to be appended to a ``.xml`` file
  produced by a previous call to this command.

``CONFIGURATION <config>``
  Specify the build configuration (e.g. ``Debug``).  If not
  specified the ``CTEST_BUILD_CONFIGURATION`` variable will be checked.
  Otherwise the ``-C <cfg>`` option given to the ``ctest(1)``
  command will be used, if any.

``FLAGS <flags>``
  Pass additional arguments to the underlying build command.
  If not specified the ``CTEST_BUILD_FLAGS`` variable will be checked.
  This can, e.g., be used to trigger a parallel build using the
  ``-j`` option of make. See the ``ProcessorCount`` module
  for an example.

``PROJECT_NAME <project-name>``
  Set the name of the project to build.  This should correspond
  to the top-level call to the ``project()`` command.
  If not specified the ``CTEST_PROJECT_NAME`` variable will be checked.

``TARGET <target-name>``
  Specify the name of a target to build.  If not specified the
  ``CTEST_BUILD_TARGET`` variable will be checked.  Otherwise the
  default target will be built.  This is the "all" target
  (called ``ALL_BUILD`` in :ref:`Visual Studio Generators`).

``NUMBER_ERRORS <num-err-var>``
  Store the number of build errors detected in the given variable.

``NUMBER_WARNINGS <num-warn-var>``
  Store the number of build warnings detected in the given variable.

``RETURN_VALUE <result-var>``
  Store the return value of the native build tool in the given variable.

``CAPTURE_CMAKE_ERROR <result-var>``
  Store in the ``<result-var>`` variable -1 if there are any errors running
  the command and prevent ctest from returning non-zero if an error occurs.

``QUIET``
  Suppress any CTest-specific non-error output that would have been
  printed to the console otherwise.  The summary of warnings / errors,
  as well as the output from the native build tool is unaffected by
  this option.

ctest_configure
---------------

Perform the :ref:`CTest Configure Step` as a :ref:`Dashboard Client`.

::

 ctest_configure([BUILD <build-dir>] [SOURCE <source-dir>] [APPEND]
                 [OPTIONS <options>] [RETURN_VALUE <result-var>] [QUIET]
                 [CAPTURE_CMAKE_ERROR <result-var>])

Configure the project build tree and record results in ``Configure.xml``
for submission with the ``ctest_submit()`` command.

The options are:

``BUILD <build-dir>``
  Specify the top-level build directory.  If not given, the
  ``CTEST_BINARY_DIRECTORY`` variable is used.

``SOURCE <source-dir>``
  Specify the source directory.  If not given, the
  ``CTEST_SOURCE_DIRECTORY`` variable is used.

``APPEND``
  Mark ``Configure.xml`` for append to results previously submitted to a
  dashboard server since the last ``ctest_start()`` call.
  Append semantics are defined by the dashboard server in use.
  This does *not* cause results to be appended to a ``.xml`` file
  produced by a previous call to this command.

``OPTIONS <options>``
  Specify command-line arguments to pass to the configuration tool.

``RETURN_VALUE <result-var>``
  Store in the ``<result-var>`` variable the return value of the native
  configuration tool.

``CAPTURE_CMAKE_ERROR <result-var>``
  Store in the ``<result-var>`` variable -1 if there are any errors running
  the command and prevent ctest from returning non-zero if an error occurs.

``QUIET``
  Suppress any CTest-specific non-error messages that would have
  otherwise been printed to the console.  Output from the underlying
  configure command is not affected.

ctest_coverage
--------------

Perform the :ref:`CTest Coverage Step` as a :ref:`Dashboard Client`.

::

 ctest_coverage([BUILD <build-dir>] [APPEND]
                [LABELS <label>...]
                [RETURN_VALUE <result-var>]
                [CAPTURE_CMAKE_ERROR <result-var]
                [QUIET]
                )

Collect coverage tool results and stores them in ``Coverage.xml``
for submission with the ``ctest_submit()`` command.

The options are:

``BUILD <build-dir>``
  Specify the top-level build directory.  If not given, the
  ``CTEST_BINARY_DIRECTORY`` variable is used.

``APPEND``
  Mark ``Coverage.xml`` for append to results previously submitted to a
  dashboard server since the last ``ctest_start()`` call.
  Append semantics are defined by the dashboard server in use.
  This does *not* cause results to be appended to a ``.xml`` file
  produced by a previous call to this command.

``LABELS``
  Filter the coverage report to include only source files labeled
  with at least one of the labels specified.

``RETURN_VALUE <result-var>``
  Store in the ``<result-var>`` variable ``0`` if coverage tools
  ran without error and non-zero otherwise.

``CAPTURE_CMAKE_ERROR <result-var>``
  Store in the ``<result-var>`` variable -1 if there are any errors running
  the command and prevent ctest from returning non-zero if an error occurs.

``QUIET``
  Suppress any CTest-specific non-error output that would have been
  printed to the console otherwise.  The summary indicating how many
  lines of code were covered is unaffected by this option.

ctest_empty_binary_directory
----------------------------

empties the binary directory

::

 ctest_empty_binary_directory( directory )

Removes a binary directory.  This command will perform some checks
prior to deleting the directory in an attempt to avoid malicious or
accidental directory deletion.

ctest_memcheck
--------------

Perform the :ref:`CTest MemCheck Step` as a :ref:`Dashboard Client`.

::

 ctest_memcheck([BUILD <build-dir>] [APPEND]
                [START <start-number>]
                [END <end-number>]
                [STRIDE <stride-number>]
                [EXCLUDE <exclude-regex>]
                [INCLUDE <include-regex>]
                [EXCLUDE_LABEL <label-exclude-regex>]
                [INCLUDE_LABEL <label-include-regex>]
                [EXCLUDE_FIXTURE <regex>]
                [EXCLUDE_FIXTURE_SETUP <regex>]
                [EXCLUDE_FIXTURE_CLEANUP <regex>]
                [PARALLEL_LEVEL <level>]
                [TEST_LOAD <threshold>]
                [SCHEDULE_RANDOM <ON|OFF>]
                [STOP_TIME <time-of-day>]
                [RETURN_VALUE <result-var>]
                [DEFECT_COUNT <defect-count-var>]
                [QUIET]
                )

Run tests with a dynamic analysis tool and store results in
``MemCheck.xml`` for submission with the ``ctest_submit()``
command.

Most options are the same as those for the ``ctest_test()`` command.

The options unique to this command are:

``DEFECT_COUNT <defect-count-var>``
  Store in the ``<defect-count-var>`` the number of defects found.

ctest_read_custom_files
-----------------------

read CTestCustom files.

::

 ctest_read_custom_files( directory ... )

Read all the CTestCustom.ctest or CTestCustom.cmake files from the
given directory.

By default, invoking ``ctest(1)`` without a script will read custom
files from the binary directory.

ctest_run_script
----------------

runs a ctest -S script

::

 ctest_run_script([NEW_PROCESS] script_file_name script_file_name1
             script_file_name2 ... [RETURN_VALUE var])

Runs a script or scripts much like if it was run from ctest -S.  If no
argument is provided then the current script is run using the current
settings of the variables.  If ``NEW_PROCESS`` is specified then each
script will be run in a separate process.If ``RETURN_VALUE`` is specified
the return value of the last script run will be put into ``var``.

ctest_sleep
-----------

sleeps for some amount of time

::

 ctest_sleep(<seconds>)

Sleep for given number of seconds.

::

 ctest_sleep(<time1> <duration> <time2>)

Sleep for t=(time1 + duration - time2) seconds if t > 0.

ctest_start
-----------

Starts the testing for a given model

::

 ctest_start(Model [TRACK <track>] [APPEND] [source [binary]] [QUIET])

Starts the testing for a given model.  The command should be called
after the binary directory is initialized.  If the 'source' and
'binary' directory are not specified, it reads the
``CTEST_SOURCE_DIRECTORY`` and ``CTEST_BINARY_DIRECTORY``.
If the track is
specified, the submissions will go to the specified track.  If APPEND
is used, the existing TAG is used rather than creating a new one based
on the current time stamp.  If ``QUIET`` is used, CTest will suppress any
non-error messages that it otherwise would have printed to the console.

If the ``CTEST_CHECKOUT_COMMAND`` variable
(or the ``CTEST_CVS_CHECKOUT`` variable)
is set, its content is treated as command-line.  The command is
invoked with the current working directory set to the parent of the source
directory, even if the source directory already exists.  This can be used
to create the source tree from a version control repository.

ctest_submit
------------

Perform the :ref:`CTest Submit Step` as a :ref:`Dashboard Client`.

::

 ctest_submit([PARTS <part>...] [FILES <file>...]
              [HTTPHEADER <header>]
              [RETRY_COUNT <count>]
              [RETRY_DELAY <delay>]
              [RETURN_VALUE <result-var>]
              [QUIET]
              )

Submit results to a dashboard server.
By default all available parts are submitted.

The options are:

``PARTS <part>...``
  Specify a subset of parts to submit.  Valid part names are::

 Start      = nothing
 Update     = ctest_update results, in Update.xml
 Configure  = ctest_configure results, in Configure.xml
 Build      = ctest_build results, in Build.xml
 Test       = ctest_test results, in Test.xml
 Coverage   = ctest_coverage results, in Coverage.xml
 MemCheck   = ctest_memcheck results, in DynamicAnalysis.xml
 Notes      = Files listed by CTEST_NOTES_FILES, in Notes.xml
 ExtraFiles = Files listed by CTEST_EXTRA_SUBMIT_FILES
 Upload     = Files prepared for upload by ctest_upload(), in Upload.xml
 Submit     = nothing

``FILES <file>...``
  Specify an explicit list of specific files to be submitted.
  Each individual file must exist at the time of the call.

``HTTPHEADER <HTTP-header>``
  Specify HTTP header to be included in the request to CDash during submission.
  This suboption can be repeated several times.

``RETRY_COUNT <count>``
  Specify how many times to retry a timed-out submission.

``RETRY_DELAY <delay>``
  Specify how long (in seconds) to wait after a timed-out submission
  before attempting to re-submit.

``RETURN_VALUE <result-var>``
  Store in the ``<result-var>`` variable ``0`` for success and
  non-zero on failure.

``QUIET``
  Suppress all non-error messages that would have otherwise been
  printed to the console.

Submit to CDash Upload API
^^^^^^^^^^^^^^^^^^^^^^^^^^

::

 ctest_submit(CDASH_UPLOAD <file> [CDASH_UPLOAD_TYPE <type>]
              [HTTPHEADER <header>]
              [RETRY_COUNT <count>]
              [RETRY_DELAY <delay>]
              [QUIET])

This second signature is used to upload files to CDash via the CDash
file upload API. The api first sends a request to upload to CDash along
with a content hash of the file. If CDash does not already have the file,
then it is uploaded. Along with the file, a CDash type string is specified
to tell CDash which handler to use to process the data.

This signature accepts the ``HTTPHEADER``, ``RETRY_COUNT``, ``RETRY_DELAY``, and
``QUIET`` options as described above.

ctest_test
----------

Perform the :ref:`CTest Test Step` as a :ref:`Dashboard Client`.

::

 ctest_test([BUILD <build-dir>] [APPEND]
            [START <start-number>]
            [END <end-number>]
            [STRIDE <stride-number>]
            [EXCLUDE <exclude-regex>]
            [INCLUDE <include-regex>]
            [EXCLUDE_LABEL <label-exclude-regex>]
            [INCLUDE_LABEL <label-include-regex>]
            [EXCLUDE_FIXTURE <regex>]
            [EXCLUDE_FIXTURE_SETUP <regex>]
            [EXCLUDE_FIXTURE_CLEANUP <regex>]
            [PARALLEL_LEVEL <level>]
            [TEST_LOAD <threshold>]
            [SCHEDULE_RANDOM <ON|OFF>]
            [STOP_TIME <time-of-day>]
            [RETURN_VALUE <result-var>]
            [CAPTURE_CMAKE_ERROR <result-var>]
            [QUIET]
            )

Run tests in the project build tree and store results in
``Test.xml`` for submission with the ``ctest_submit()`` command.

The options are:

``BUILD <build-dir>``
  Specify the top-level build directory.  If not given, the
  ``CTEST_BINARY_DIRECTORY`` variable is used.

``APPEND``
  Mark ``Test.xml`` for append to results previously submitted to a
  dashboard server since the last ``ctest_start()`` call.
  Append semantics are defined by the dashboard server in use.
  This does *not* cause results to be appended to a ``.xml`` file
  produced by a previous call to this command.

``START <start-number>``
  Specify the beginning of a range of test numbers.

``END <end-number>``
  Specify the end of a range of test numbers.

``STRIDE <stride-number>``
  Specify the stride by which to step across a range of test numbers.

``EXCLUDE <exclude-regex>``
  Specify a regular expression matching test names to exclude.

``INCLUDE <include-regex>``
  Specify a regular expression matching test names to include.
  Tests not matching this expression are excluded.

``EXCLUDE_LABEL <label-exclude-regex>``
  Specify a regular expression matching test labels to exclude.

``INCLUDE_LABEL <label-include-regex>``
  Specify a regular expression matching test labels to include.
  Tests not matching this expression are excluded.

``EXCLUDE_FIXTURE <regex>``
  If a test in the set of tests to be executed requires a particular fixture,
  that fixture's setup and cleanup tests would normally be added to the test
  set automatically. This option prevents adding setup or cleanup tests for
  fixtures matching the ``<regex>``. Note that all other fixture behavior is
  retained, including test dependencies and skipping tests that have fixture
  setup tests that fail.

``EXCLUDE_FIXTURE_SETUP <regex>``
  Same as ``EXCLUDE_FIXTURE`` except only matching setup tests are excluded.

``EXCLUDE_FIXTURE_CLEANUP <regex>``
  Same as ``EXCLUDE_FIXTURE`` except only matching cleanup tests are excluded.

``PARALLEL_LEVEL <level>``
  Specify a positive number representing the number of tests to
  be run in parallel.

``TEST_LOAD <threshold>``
  While running tests in parallel, try not to start tests when they
  may cause the CPU load to pass above a given threshold.  If not
  specified the ``CTEST_TEST_LOAD`` variable will be checked,
  and then the ``--test-load`` command-line argument to ``ctest(1)``.
  See also the ``TestLoad`` setting in the :ref:`CTest Test Step`.

``SCHEDULE_RANDOM <ON|OFF>``
  Launch tests in a random order.  This may be useful for detecting
  implicit test dependencies.

``STOP_TIME <time-of-day>``
  Specify a time of day at which the tests should all stop running.

``RETURN_VALUE <result-var>``
  Store in the ``<result-var>`` variable ``0`` if all tests passed.
  Store non-zero if anything went wrong.

``CAPTURE_CMAKE_ERROR <result-var>``
  Store in the ``<result-var>`` variable -1 if there are any errors running
  the command and prevent ctest from returning non-zero if an error occurs.

``QUIET``
  Suppress any CTest-specific non-error messages that would have otherwise
  been printed to the console.  Output from the underlying test command is not
  affected.  Summary info detailing the percentage of passing tests is also
  unaffected by the ``QUIET`` option.

See also the ``CTEST_CUSTOM_MAXIMUM_PASSED_TEST_OUTPUT_SIZE``
and ``CTEST_CUSTOM_MAXIMUM_FAILED_TEST_OUTPUT_SIZE`` variables.

ctest_update
------------

Perform the :ref:`CTest Update Step` as a :ref:`Dashboard Client`.

::

 ctest_update([SOURCE <source-dir>] [RETURN_VALUE <result-var>] [QUIET])

Update the source tree from version control and record results in
``Update.xml`` for submission with the ``ctest_submit()`` command.

The options are:

``SOURCE <source-dir>``
  Specify the source directory.  If not given, the
  ``CTEST_SOURCE_DIRECTORY`` variable is used.

``RETURN_VALUE <result-var>``
  Store in the ``<result-var>`` variable the number of files
  updated or ``-1`` on error.

``QUIET``
  Tell CTest to suppress most non-error messages that it would
  have otherwise printed to the console.  CTest will still report
  the new revision of the repository and any conflicting files
  that were found.

The update always follows the version control branch currently checked
out in the source directory.  See the :ref:`CTest Update Step`
documentation for more information.

ctest_upload
------------

Upload files to a dashboard server as a :ref:`Dashboard Client`.

::

 ctest_upload(FILES <file>... [QUIET] [CAPTURE_CMAKE_ERROR <result-var>])

The options are:

``FILES <file>...``
  Specify a list of files to be sent along with the build results to the
  dashboard server.

``QUIET``
  Suppress any CTest-specific non-error output that would have been
  printed to the console otherwise.

``CAPTURE_CMAKE_ERROR <result-var>``
  Store in the ``<result-var>`` variable -1 if there are any errors running
  the command and prevent ctest from returning non-zero if an error occurs.

Deprecated Commands
===================

These commands are available only for compatibility with older
versions of CMake.  Do not use them in new code.

build_name
----------

Disallowed.  See CMake Policy ``CMP0036``.

Use ``${CMAKE_SYSTEM}`` and ``${CMAKE_CXX_COMPILER}`` instead.

::

 build_name(variable)

Sets the specified variable to a string representing the platform and
compiler settings.  These values are now available through the
``CMAKE_SYSTEM`` and
``CMAKE_CXX_COMPILER`` variables.

exec_program
------------

Deprecated.  Use the ``execute_process()`` command instead.

Run an executable program during the processing of the CMakeList.txt
file.

::

 exec_program(Executable [directory in which to run]
              [ARGS <arguments to executable>]
              [OUTPUT_VARIABLE <var>]
              [RETURN_VALUE <var>])

The executable is run in the optionally specified directory.  The
executable can include arguments if it is double quoted, but it is
better to use the optional ``ARGS`` argument to specify arguments to the
program.  This is because cmake will then be able to escape spaces in
the executable path.  An optional argument ``OUTPUT_VARIABLE`` specifies a
variable in which to store the output.  To capture the return value of
the execution, provide a ``RETURN_VALUE``.  If ``OUTPUT_VARIABLE`` is
specified, then no output will go to the stdout/stderr of the console
running cmake.

export_library_dependencies
---------------------------

Disallowed.  See CMake Policy ``CMP0033``.

Use ``install(EXPORT)`` or ``export()`` command.

This command generates an old-style library dependencies file.
Projects requiring CMake 2.6 or later should not use the command.  Use
instead the ``install(EXPORT)`` command to help export targets from an
installation tree and the ``export()`` command to export targets from a
build tree.

The old-style library dependencies file does not take into account
per-configuration names of libraries or the
``LINK_INTERFACE_LIBRARIES`` target property.

::

 export_library_dependencies(<file> [APPEND])

Create a file named ``<file>`` that can be included into a CMake listfile
with the INCLUDE command.  The file will contain a number of SET
commands that will set all the variables needed for library dependency
information.  This should be the last command in the top level
CMakeLists.txt file of the project.  If the ``APPEND`` option is
specified, the SET commands will be appended to the given file instead
of replacing it.

install_files
-------------

Deprecated.  Use the ``install(FILES)`` command instead.

This command has been superceded by the ``install()`` command.  It is
provided for compatibility with older CMake code.  The ``FILES`` form is
directly replaced by the ``FILES`` form of the ``install()``
command.  The regexp form can be expressed more clearly using the ``GLOB``
form of the ``file()`` command.

::

 install_files(<dir> extension file file ...)

Create rules to install the listed files with the given extension into
the given directory.  Only files existing in the current source tree
or its corresponding location in the binary tree may be listed.  If a
file specified already has an extension, that extension will be
removed first.  This is useful for providing lists of source files
such as foo.cxx when you want the corresponding foo.h to be installed.
A typical extension is '.h'.

::

 install_files(<dir> regexp)

Any files in the current source directory that match the regular
expression will be installed.

::

 install_files(<dir> FILES file file ...)

Any files listed after the ``FILES`` keyword will be installed explicitly
from the names given.  Full paths are allowed in this form.

The directory ``<dir>`` is relative to the installation prefix, which is
stored in the variable ``CMAKE_INSTALL_PREFIX``.

install_programs
----------------

Deprecated. Use the ``install(PROGRAMS)`` command instead.

This command has been superceded by the ``install()`` command.  It is
provided for compatibility with older CMake code.  The ``FILES`` form is
directly replaced by the ``PROGRAMS`` form of the ``install()``
command.  The regexp form can be expressed more clearly using the ``GLOB``
form of the ``file()`` command.

::

 install_programs(<dir> file1 file2 [file3 ...])
 install_programs(<dir> FILES file1 [file2 ...])

Create rules to install the listed programs into the given directory.
Use the ``FILES`` argument to guarantee that the file list version of the
command will be used even when there is only one argument.

::

 install_programs(<dir> regexp)

In the second form any program in the current source directory that
matches the regular expression will be installed.

This command is intended to install programs that are not built by
cmake, such as shell scripts.  See the ``TARGETS`` form of the
``install()`` command to create installation rules for targets built
by cmake.

The directory ``<dir>`` is relative to the installation prefix, which is
stored in the variable ``CMAKE_INSTALL_PREFIX``.

install_targets
---------------

Deprecated. Use the ``install(TARGETS)`` command instead.

This command has been superceded by the ``install()`` command.  It is
provided for compatibility with older CMake code.

::

 install_targets(<dir> [RUNTIME_DIRECTORY dir] target target)

Create rules to install the listed targets into the given directory.
The directory ``<dir>`` is relative to the installation prefix, which is
stored in the variable ``CMAKE_INSTALL_PREFIX``.  If
``RUNTIME_DIRECTORY`` is specified, then on systems with special runtime
files (Windows DLL), the files will be copied to that directory.

load_command
------------

Disallowed.  See CMake Policy ``CMP0031``.

Load a command into a running CMake.

::

 load_command(COMMAND_NAME <loc1> [loc2 ...])

The given locations are searched for a library whose name is
cmCOMMAND_NAME.  If found, it is loaded as a module and the command is
added to the set of available CMake commands.  Usually,
``try_compile()`` is used before this command to compile the
module.  If the command is successfully loaded a variable named

::

 CMAKE_LOADED_COMMAND_<COMMAND_NAME>

will be set to the full path of the module that was loaded.  Otherwise
the variable will not be set.

make_directory
--------------

Deprecated. Use the ``file(MAKE_DIRECTORY)`` command instead.

::

 make_directory(directory)

Creates the specified directory.  Full paths should be given.  Any
parent directories that do not exist will also be created.  Use with
care.

output_required_files
---------------------

Disallowed.  See CMake Policy ``CMP0032``.

Approximate C preprocessor dependency scanning.

This command exists only because ancient CMake versions provided it.
CMake handles preprocessor dependency scanning automatically using a
more advanced scanner.

::

 output_required_files(srcfile outputfile)

Outputs a list of all the source files that are required by the
specified srcfile.  This list is written into outputfile.  This is
similar to writing out the dependencies for srcfile except that it
jumps from .h files into .cxx, .c and .cpp files if possible.

remove
------

Deprecated. Use the ``list(REMOVE_ITEM)`` command instead.

::

 remove(VAR VALUE VALUE ...)

Removes ``VALUE`` from the variable ``VAR``.  This is typically used to
remove entries from a vector (e.g.  semicolon separated list).  ``VALUE``
is expanded.

subdir_depends
--------------

Disallowed.  See CMake Policy ``CMP0029``.

Does nothing.

::

 subdir_depends(subdir dep1 dep2 ...)

Does not do anything.  This command used to help projects order
parallel builds correctly.  This functionality is now automatic.

subdirs
-------

Deprecated. Use the ``add_subdirectory()`` command instead.

Add a list of subdirectories to the build.

::

 subdirs(dir1 dir2 ...[EXCLUDE_FROM_ALL exclude_dir1 exclude_dir2 ...]
         [PREORDER] )

Add a list of subdirectories to the build.  The ``add_subdirectory()``
command should be used instead of ``subdirs`` although ``subdirs`` will still
work.  This will cause any CMakeLists.txt files in the sub directories
to be processed by CMake.  Any directories after the ``PREORDER`` flag are
traversed first by makefile builds, the ``PREORDER`` flag has no effect on
IDE projects.  Any directories after the ``EXCLUDE_FROM_ALL`` marker will
not be included in the top level makefile or project file.  This is
useful for having CMake create makefiles or projects for a set of
examples in a project.  You would want CMake to generate makefiles or
project files for all the examples at the same time, but you would not
want them to show up in the top level project or be built each time
make is run from the top.

use_mangled_mesa
----------------

Disallowed.  See CMake Policy ``CMP0030``.

Copy mesa headers for use in combination with system GL.

::

 use_mangled_mesa(PATH_TO_MESA OUTPUT_DIRECTORY)

The path to mesa includes, should contain gl_mangle.h.  The mesa
headers are copied to the specified output directory.  This allows
mangled mesa headers to override other GL headers by being added to
the include directory path earlier.

utility_source
--------------

Disallowed.  See CMake Policy ``CMP0034``.

Specify the source tree of a third-party utility.

::

 utility_source(cache_entry executable_name
                path_to_source [file1 file2 ...])

When a third-party utility's source is included in the distribution,
this command specifies its location and name.  The cache entry will
not be set unless the ``path_to_source`` and all listed files exist.  It
is assumed that the source tree of the utility will have been built
before it is needed.

When cross compiling CMake will print a warning if a ``utility_source()``
command is executed, because in many cases it is used to build an
executable which is executed later on.  This doesn't work when cross
compiling, since the executable can run only on their target platform.
So in this case the cache entry has to be adjusted manually so it
points to an executable which is runnable on the build host.

variable_requires
-----------------

Disallowed.  See CMake Policy ``CMP0035``.

Use the ``if()`` command instead.

Assert satisfaction of an option's required variables.

::

 variable_requires(TEST_VARIABLE RESULT_VARIABLE
                   REQUIRED_VARIABLE1
                   REQUIRED_VARIABLE2 ...)

The first argument (``TEST_VARIABLE``) is the name of the variable to be
tested, if that variable is false nothing else is done.  If
``TEST_VARIABLE`` is true, then the next argument (``RESULT_VARIABLE``)
is a variable that is set to true if all the required variables are set.
The rest of the arguments are variables that must be true or not set
to NOTFOUND to avoid an error.  If any are not true, an error is
reported.

write_file
----------

Deprecated. Use the ``file(WRITE)`` command instead.

::

 write_file(filename "message to write"... [APPEND])

The first argument is the file name, the rest of the arguments are
messages to write.  If the argument ``APPEND`` is specified, then the
message will be appended.

NOTE 1: ``file(WRITE)``  and ``file(APPEND)``  do exactly
the same as this one but add some more functionality.

NOTE 2: When using ``write_file`` the produced file cannot be used as an
input to CMake (CONFIGURE_FILE, source file ...) because it will lead
to an infinite loop.  Use ``configure_file()`` if you want to
generate input files to CMake.