cmake_minimum_required(VERSION 4.0.0)

project(
  qt6_add_library_CMP0156
  VERSION 0.1
  LANGUAGES CXX)

set(CMAKE_CXX_STANDARD_REQUIRED ON)


find_package(
    Qt6 REQUIRED
    COMPONENTS Quick)

qt_standard_project_setup(REQUIRES 6.8)

qt6_add_library(testLib STATIC test.cpp test.h)

qt_add_executable(appqt6_add_library_CMP0156 main.cpp)

[cmake] Running C:\Program Files\CMake\bin\cmake.exe -S C:/workspace/Qt/qt6_add_library_CMP0156 -B C:/workspace/Qt/qt6_add_library_CMP0156/build/Desktop_Qt_6_10_0_MSVC2022_64bit-Debug in C:\workspace\Qt\qt6_add_library_CMP0156\build\Desktop_Qt_6_10_0_MSVC2022_64bit-Debug.
[cmake] CMake Warning at C:/Qt/6.10.0/msvc2022_64/lib/cmake/Qt6/QtPublicCMakeVersionHelpers.cmake:184 (message):
[cmake]   CMP0156 is set to 'NEW'.  Qt forces the 'OLD' behavior of this policy for
[cmake]   non-Apple platforms by default.  Set QT_FORCE_CMP0156_TO_VALUE=NEW to force
[cmake]   the 'NEW' behavior for Qt commands that create library or executable
[cmake]   targets.
[cmake] Call Stack (most recent call first):
[cmake]   C:/Qt/6.10.0/msvc2022_64/lib/cmake/Qt6Core/Qt6CoreMacros.cmake:2856 (__qt_internal_set_cmp0156)
[cmake]   C:/Qt/6.10.0/msvc2022_64/lib/cmake/Qt6Core/Qt6CoreMacros.cmake:2770 (_qt_internal_add_library)
[cmake]   CMakeLists.txt:22 (qt6_add_library)
[cmake] 
[cmake] 
[cmake] CMake Warning at C:/Qt/6.10.0/msvc2022_64/lib/cmake/Qt6/QtPublicCMakeVersionHelpers.cmake:184 (message):
[cmake]   CMP0156 is set to 'NEW'.  Qt forces the 'OLD' behavior of this policy for
[cmake]   non-Apple platforms by default.  Set QT_FORCE_CMP0156_TO_VALUE=NEW to force
[cmake]   the 'NEW' behavior for Qt commands that create library or executable
[cmake]   targets.
[cmake] Call Stack (most recent call first):
[cmake]   C:/Qt/6.10.0/msvc2022_64/lib/cmake/Qt6Core/Qt6CoreMacros.cmake:746 (__qt_internal_set_cmp0156)
[cmake]   C:/Qt/6.10.0/msvc2022_64/lib/cmake/Qt6Core/Qt6CoreMacros.cmake:671 (_qt_internal_create_executable)
[cmake]   C:/Qt/6.10.0/msvc2022_64/lib/cmake/Qt6Core/Qt6CoreMacros.cmake:1000 (qt6_add_executable)
[cmake]   CMakeLists.txt:24 (qt_add_executable)
[cmake] 
[cmake] 
[cmake] -- Configuring done (0.6s)
[cmake] -- Generating done (0.2s)
[cmake] -- Build files have been written to: C:/workspace/Qt/qt6_add_library_CMP0156/build/Desktop_Qt_6_10_0_MSVC2022_64bit-Debug
[cmake] 
[cmake] Elapsed time: 00:01.

cmake_minimum_required(VERSION 3.31.0)

cmake_policy(GET CMP0156 policy_value)

if(policy_value STREQUAL "")
message(STATUS "CMP0156 policy is UNSET (will default to NEW for CMake 3.31+)")
else()
message(STATUS "CMP0156 policy is set to: ${policy_value}")
endif()

cmake_minimum_required(VERSION 3.29.0)
cmake_policy(GET CMP0156 policy_value_329)
message(STATUS "With cmake_minimum_required 3.29: CMP0156 = '${policy_value_329}'")

cmake_minimum_required(VERSION 3.28.0)
cmake_policy(GET CMP0156 policy_value_328)
message(STATUS "With cmake_minimum_required 3.28: CMP0156 = '${policy_value_328}'")

cmake --version
cmake version 4.1.1

cmake -P test_cmp0156.cmake
– CMP0156 policy is set to: NEW
– With cmake_minimum_required 3.29: CMP0156 = 'NEW'
– With cmake_minimum_required 3.28: CMP0156 = ''