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(3RT), _exit(2), or one of the exec functions (see exec(2)) . Calls to sem_open(3RT) 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:

EACCES

Permission is denied to unlink the named semaphore.

ENAMETOOLONG

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

ENOENT

The named semaphore does not exist.

ENOSYS

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

See attributes(5) for descriptions of the following attributes:

exec(2), exit(2), sem_close(3RT), sem_open(3RT), attributes(5)

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.