cc -pipe -O   -pthread  -Wall -Wextra -Werror=implicit-function-declaration time/timer_create.c -o time/timer_create -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread -lrt  -lrt -lcrypt
time/timer_create.c: In function 'main':
time/timer_create.c:17:7: error: implicit declaration of function 'timer_create'; did you mean 'timerclear'? [-Werror=implicit-function-declaration]
  if ( timer_create(CLOCK_MONOTONIC, &event, &timer) < 0 )
       ^~~~~~~~~~~~
       timerclear
cc1: some warnings being treated as errors