SEM_UNLINK(3C) Standard C Library Functions SEM_UNLINK(3C)

sem_unlink - remove a named semaphore

#include <semaphore.h>
int sem_unlink(const char *name);

The sem_unlink() function removes the semaphore named by the string name. If the semaphore named by name is currently referenced by other processes, then sem_unlink() has no effect on the state of the semaphore. If one or more processes have the semaphore open when sem_unlink() is called, destruction of the semaphore is postponed until all references to the semaphore have been destroyed by calls to sem_close(3C), _Exit(2), or one of the exec functions (see exec(2)) . Calls to sem_open(3C) to re-create or re-connect to the semaphore refer to a new semaphore after sem_unlink() is called. The sem_unlink() call does not block until all references have been destroyed; it returns immediately.

Upon successful completion, sem_unlink() returns 0. Otherwise, the semaphore is not changed and the function returns a value of −1 and sets errno to indicate the error.

The sem_unlink() function will fail if:


Permission is denied to unlink the named semaphore.


The length of name string exceeds PATH_MAX, or a pathname component is longer than NAME_MAX while _POSIX_NO_TRUNC is in effect.


The named semaphore does not exist.


The sem_unlink() function is not supported by the system.

See attributes(7) for descriptions of the following attributes:

Interface Stability Committed
MT-Level MT-Safe
Standard See standards(7).

exec(2), exit(2), sem_close(3C), sem_open(3C), attributes(7), standards(7)

Solaris 2.6 was the first release to support the Asynchronous Input and Output option. Prior to this release, this function always returned −1 and set errno to ENOSYS.

February 5, 2008 OmniOS