The mq_unlink() function removes the message queue named by the pathname name. After a successful call to mq_unlink() with name, a call to mq_open(3RT) with name fails if the flag O_CREAT is not set in flags. If one or more processes have the message queue open when mq_unlink() is called, destruction of the message queue is postponed until all references to the message queue have been closed. Calls to mq_open(3RT) to re-create the message queue may fail until the message queue is actually removed. However, the mq_unlink() call need not block until all references have been closed; it may return immediately.

Upon successful completion, mq_unlink() returns 0; otherwise, the named message queue is not changed by this function call, the function returns -1 and sets errno to indicate the error.

The mq_unlink() function will fail if:

EACCESS

Permission is denied to unlink the named message queue.

ENAMETOOLONG

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

ENOENT

The named message queue, name, does not exist.

ENOSYS

mq_unlink() is not supported by the system.

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

mq_close(3RT), mq_open(3RT), attributes(5), mqueue(3HEAD)

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.