# CXX_SCAN_FOR_MODULES

Added in version 4.4.

`CXX_SCAN_FOR_MODULES` is a boolean specifying whether CMake will scan the file set's sources for C++ module dependencies. See also the `CXX_SCAN_FOR_MODULES` source file property and the `CXX_SCAN_FOR_MODULES` target property settings.

When this property is set `ON`, CMake will scan the file set's sources at build time and add module dependency information to the compile line as necessary. When this property is set `OFF`, CMake will not scan the sources at build time. When this property is unset, the `CXX_SCAN_FOR_MODULES` source file property and `CXX_SCAN_FOR_MODULES` target property are consulted, in that order.

Note that scanning is only performed if C++20 or higher is enabled for the target and the source uses the `CXX` language. Scanning for modules in sources belonging to file sets of type `CXX_MODULES` is always performed.