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mqueuefs(5) [freebsd man page]

MQUEUEFS(5)						      BSD File Formats Manual						       MQUEUEFS(5)

mqueuefs -- POSIX message queue file system SYNOPSIS
To link into kernel: options P1003_1B_MQUEUE To load as a kernel loadable module: kldload mqueuefs DESCRIPTION
The mqueuefs module will permit the FreeBSD kernel to support POSIX message queue. The module contains system calls to manipulate POSIX mes- sage queues. It also contains a file system to implement a view for all message queues of the system. This helps users to keep track of their message queues and make it more easily usable without having to invent additional tools. The most common usage is as follows: mount -t mqueuefs null /mnt/mqueue where /mnt/mqueue is a mount point. It is possible to define an entry in /etc/fstab that looks similar to: null /mnt/mqueue mqueuefs rw 0 0 This will mount mqueuefs at the /mnt/mqueue mount point during system boot. Using /mnt/mqueue as a permanent mount point is not advised as its intention has always been to be a temporary mount point. See hier(7) for more information on FreeBSD directory layout. Some common tools can be used on the file system, e.g.: cat(1), chmod(1), chown(8), ls(1), rm(1), etc. To use only the message queue system calls, it is not necessary for user to mount the file system, just load the module or compile it into the kernel. Manually creating a file, for example, ``touch /mnt/mqueue/myqueue'', will create a message queue named myqueue in the kernel, default message queue attributes will be applied to the queue. It is not advised to use this method to create a queue; it is better to use the mq_open(2) system call to create a queue as it allows the user to specify different attributes. To see the queue's attributes, just read the file: cat /mnt/mqueue/myqueue SEE ALSO
mq_open(2), nmount(2), unmount(2), mount(8), umount(8) AUTHORS
This manual page was written by David Xu <>. BSD
November 30, 2005 BSD

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mq_unlink(3C)						   Standard C Library Functions 					     mq_unlink(3C)

mq_unlink - remove a message queue SYNOPSIS
#include <mqueue.h> int mq_unlink(const char *name); DESCRIPTION
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(3C) 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(3C) 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. RETURN VALUES
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. ERRORS
The mq_unlink() function will fail if: EACCES 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. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ |ATTRIBUTE TYPE |ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Committed | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ |Standard |See standards(5). | +-----------------------------+-----------------------------+ SEE ALSO
mqueue.h(3HEAD), mq_close(3C), mq_open(3C), attributes(5), standards(5) NOTES
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. SunOS 5.11 5 Feb 2008 mq_unlink(3C)
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