cc -pipe -O   -pthread  -Wall -Wextra -Werror=implicit-function-declaration pthread/pthread_rwlock_clockrdlock.c -o pthread/pthread_rwlock_clockrdlock -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread -lrt  -lrt -lcrypt
pthread/pthread_rwlock_clockrdlock.c: In function 'main':
pthread/pthread_rwlock_clockrdlock.c:16:16: error: implicit declaration of function 'pthread_rwlock_clockrdlock'; did you mean 'pthread_rwlock_tryrdlock'? [-Werror=implicit-function-declaration]
  if ( (errno = pthread_rwlock_clockrdlock(&rwlock, CLOCK_MONOTONIC,
                ^~~~~~~~~~~~~~~~~~~~~~~~~~
                pthread_rwlock_tryrdlock
cc1: some warnings being treated as errors