When this property is ON, CMake will generate the -p path prefix option for moc on AUTOMOC enabled Qt targets.

To generate the path prefix, CMake tests if the header compiled by moc is in any of the target include directories. If so, CMake will compute the relative path accordingly. If the header is not in the include directories, CMake will omit the -p path prefix option. moc usually generates a relative include path in that case.

AUTOMOC_PATH_PREFIX is initialized from the variable CMAKE_AUTOMOC_PATH_PREFIX, which is OFF by default.

See the cmake-qt(7) manual for more information on using CMake with Qt.

Reproducible builds

For reproducible builds it is recommended to keep headers that are moc compiled in one of the target include directories and set AUTOMOC_PATH_PREFIX to ON. This ensures that:

  • moc output files are identical on different build setups,

  • moc output files will compile correctly when the source and/or build directory is a symbolic link.