The mq_close() function removes the association between the message queue descriptor, mqdes, and its message queue. The results of using this message queue descriptor after successful return from this mq_close(), and until the return of this message queue descriptor from a subsequent mq_open(3RT), are undefined.

If the process (or thread) has successfully attached a notification request to the message queue via this mqdes, this attachment is removed and the message queue is available for another process to attach for notification.

Upon successful completion, mq_close() returns 0; otherwise, the function returns -1 and sets errno to indicate the error condition.

The mq_close() function will fail if:

EBADF

The mqdes argument is an invalid message queue descriptor.

ENOSYS

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

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

mq_notify(3RT), mq_open(3RT), mq_unlink(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.