QFile::resize() documentation is flawed.

Please remove "if the file" from the second sentence.

bool QFile::resize ( qint64 sz )
Sets the file size (in bytes) sz. Returns true if the file if the resize succeeds; false otherwise. If sz is larger than the file currently is the new bytes will be set to 0, if sz is smaller the file is simply truncated.

See also size() and setFileName().