cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations time/timer_gettime.c -o time/timer_gettime -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
time/timer_gettime.c:5:44: error: use of undeclared identifier 'timer_gettime'; did you mean 'clock_gettime'?
int (*foo)(timer_t, struct itimerspec *) = timer_gettime;
                                           ^~~~~~~~~~~~~
                                           clock_gettime
/usr/include/time.h:150:5: note: 'clock_gettime' declared here
int clock_gettime(clockid_t, struct timespec *);
    ^
time/timer_gettime.c:5:7: error: incompatible function pointer types initializing 'int (*)(timer_t, struct itimerspec *)' (aka 'int (*)(int, struct itimerspec *)') with an expression of type 'int (clockid_t, struct timespec *)' (aka 'int (int, struct timespec *)') [-Werror,-Wincompatible-function-pointer-types]
int (*foo)(timer_t, struct itimerspec *) = timer_gettime;
      ^                                    ~~~~~~~~~~~~~
2 errors generated.