MQ_UNLINK(3POSIX)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME
mq_unlink — remove a message queue (REALTIME)

SYNOPSIS

#include <mqueue.h>

int mq_unlink(const char *name);

DESCRIPTION
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() to behave as if no message queue of this name exists (that is, mq_open() will fail if O_CREAT is not set, or will create a new message queue if O_CREAT is set).

RETURN VALUE
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 errno to indicate the error.

ERRORS
The mq_unlink() function shall fail if:

EACCES
    Permission is denied to unlink the named message queue.

EINTR
    The call to mq_unlink() blocked waiting for all references to the named message queue to be closed and a signal interrupted the call.

ENOENT
    The named message queue does not exist.

The mq_unlink() function may fail if:

ENAMETOOLONG
    The length of the name argument exceeds {_POSIX_PATH_MAX} on systems that do not support the XSI option 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 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 mq_open() call shall not give an [ENAMETOOLONG] error.

The following sections are informative.

EXAMPLES
None.

APPLICATION USAGE
None.

RATIONALE
None.

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

SEE ALSO
mq_close(), mq_open(), msgctl(), msgget(), msgrcv(), msgsnd()

The Base Definitions volume of POSIX.1-2017, <mqueue.h>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .