/opt/IBM/openxlC/17.1.1/bin/ibm-clang -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 -latomic
sys_shm/SHM_FAILED.c:8:20: error: use of undeclared identifier 'SHM_FAILED'
void * const foo = SHM_FAILED;
                   ^
1 error generated.