cc -O2 -pipe -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sys_shm/SHM_FAILED.c -o sys_shm/SHM_FAILED -D_POSIX_C_SOURCE=202405L  -lm -lpthread -lrt  -lstdthreads -lcrypt
sys_shm/SHM_FAILED.c:8:20: error: use of undeclared identifier 'SHM_FAILED'
    8 | void * const foo = SHM_FAILED;
      |                    ^
1 error generated.