# CXX_SCAN_FOR_MODULES

Added in version 3.28.

`CXX_SCAN_FOR_MODULES` is a boolean specifying whether CMake will scan C++ sources in the target for module dependencies. See also the `CXX_SCAN_FOR_MODULES` for per-source settings which, if set, overrides the target-wide settings.

This property is initialized by the value of the `CMAKE_CXX_SCAN_FOR_MODULES` variable if it is set when a target is created.

When this property is set `ON` or unset, CMake will scan the target's `CXX` 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 target's `CXX` sources at build time.

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