// commit: f70375df85d26235a45e74559afd69be59e5ff99 2020-10-28

#define _GNU_SOURCE 1

#include <stdlib.h>

#include <semaphore.h>

int main()

{

	char buf[] = "mysemXXXXXX";

	if (!mktemp(buf)) return 1;

	// open twice

	sem_t *sem = sem_open(buf, O_CREAT|O_EXCL, 0600);

	sem_open(buf, 0);

	sem_unlink(buf);

	// close once

	sem_close(sem);

	// semaphore should be still mapped

	sem_post(sem);

}