CFLAGS — CMake 4.3.3 Documentation

# CFLAGS

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Add default compilation flags to be used when compiling `C` files.

CMake uses this environment variable value, in combination with its own builtin default flags for the toolchain, to initialize and store the `CMAKE_C_FLAGS` cache entry. This occurs the first time a build tree is configured for language `C`. For any configuration run (including the first), the environment variable will be ignored if the `CMAKE_C_FLAGS` variable is already defined.

See also `CMAKE_C_FLAGS_INIT`.