cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations sched/sched_getparam.c -o sched/sched_getparam -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
sched/sched_getparam.c:6:43: error: use of undeclared identifier 'sched_getparam'
int (*foo)(pid_t, struct sched_param *) = sched_getparam;
                                          ^
1 error generated.