MQ_UNLINK(3) Library Functions Manual MQ_UNLINK(3)

mq_unlink — remove a message queue (REALTIME)


#include <mqueue.h>

int mq_unlink(const char *name);

The mq_unlink () function shall remove the message queue named by the string name. If one or more processes have the message queue open when mq_unlink () is called, destruction of the message queue shall be postponed until all references to the message queue have been closed. However, the mq_unlink () call need not block until all references have been closed; it may return immediately.

After a successful call to mq_unlink (), reuse of the name shall subsequently cause mq_open(3) to behave as if no message queue of this name exists (that is, mq_open(3) will fail if O_CREAT is not set, or will create a new message queue if O_CREAT is set).

Upon successful completion, the function shall return a value of zero. Otherwise, the named message queue shall be unchanged by this function call, and the function shall return a value of -1 and set to indicate the error.

The mq_unlink () function shall fail if:

Permission is denied to unlink the named message queue.
The named message queue does not exist.

The mq_unlink () function may fail if:

The length of the name argument exceeds {_POSIX_PATH_MAX} on systems that do not support the XSI option [XSI] or exceeds {_XOPEN_PATH_MAX} on XSI systems, or has a pathname component that is longer than {_POSIX_NAME_MAX} on systems that do not support the XSI option [XSI] or longer than {_XOPEN_NAME_MAX} on XSI systems. A call to mq_unlink () with a name argument that contains the same message queue name as was previously used in a successful () call shall not give an [ENAMETOOLONG] error.

None.

None.

None.

A future version might require the mq_open(3) and mq_unlink () functions to have semantics similar to normal file system operations.

mq_close(3) , mq_open(3) , msgctl(3) , msgget(3) , msgrcv(3) , msgsnd(3)

XBD <mqueue.h>

First released in Issue 5. Included for alignment with the POSIX Realtime Extension.

The mq_unlink () function is marked as part of the Message Passing option.

The Open Group Corrigendum U021/5 is applied, clarifying that upon unsuccessful completion, the named message queue is unchanged by this function.

The [ENOSYS] error condition has been removed as stubs need not be provided if an implementation does not support the Message Passing option.

Austin Group Interpretation 1003.1-2001 #077 is applied, changing [ENAMETOOLONG] from a ``shall fail'' to a ``may fail'' error .

Austin Group Interpretation 1003.1-2001 #141 is applied.

January 1, 2008 posix.fail