CFLAGS ------ .. include:: ENV_VAR.txt Default compilation flags to be used when compiling ``C`` files. Will only be used by CMake on the first configuration to determine ``CC`` default compilation flags, after which the value for ``CFLAGS`` is stored in the cache as :variable:`CMAKE_C_FLAGS _FLAGS>`. For any configuration run (including the first), the environment variable will be ignored if the :variable:`CMAKE_C_FLAGS _FLAGS>` variable is defined.