cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration semaphore/sem_open.c -o semaphore/sem_open -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
semaphore/sem_open.c: In function ‘main’:
semaphore/sem_open.c:18:30: error: implicit declaration of function ‘sem_open’ [-Wimplicit-function-declaration]
   18 |                 sem_t* sem = sem_open(path, O_CREAT | O_EXCL, 0600, 1);
      |                              ^~~~~~~~
semaphore/sem_open.c:18:30: error: initialization of ‘sem_t *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
semaphore/sem_open.c:26:17: error: implicit declaration of function ‘sem_close’; did you mean ‘sem_post’? [-Wimplicit-function-declaration]
   26 |                 sem_close(sem);
      |                 ^~~~~~~~~
      |                 sem_post
semaphore/sem_open.c:27:17: error: implicit declaration of function ‘sem_unlink’; did you mean ‘symlink’? [-Wimplicit-function-declaration]
   27 |                 sem_unlink(path);
      |                 ^~~~~~~~~~
      |                 symlink