06-11-2012
They're still not 'real' files. Like /proc/, it's a special filesystem that exists only in the kernel's imagination.
10 More Discussions You Might Find Interesting
1. Programming
How can I increase the POSIX Msg Q parameter SC_MQ_PRIO_MAX? The maximum is defined as 32. Can I increase the number? If so, how?
Deepa (0 Replies)
Discussion started by: Deepa
0 Replies
2. HP-UX
Hello,
J work on a HP.
I want to create message queue by using mq_open with this parameters:
mq_open(p,O_CREAT|O_WRONLY|O_EXCL|0_NONBLOCK,0600,&queue_attr)
with p char
and the function returns the value -1 and errno equal 2.
can you help me ?
Thank. (3 Replies)
Discussion started by: AUBERT
3 Replies
3. HP-UX
Hello,
My question is related to "pipcs -qa" command under HP-UX 11i PA-RISC 64 bits.
We have a little C program that creates posix ipc message queues using the mq_open() system function.
The program fail with 'No space left on device' error when we create big queues. What is the system... (6 Replies)
Discussion started by: cadanir
6 Replies
4. Programming
Hello,
i need to write a message queue "chat server", that should work only localy.
Can anyone please help me with some ideas and peshaps code. I'm studying the UNIX IPC mechanisms right now. So far, i understand how it works but i still cannot get an idea how to write a chat programm...
... (2 Replies)
Discussion started by: etenv
2 Replies
5. Linux
Hi all,
Please tell me how to change POSIX message queue maximum size? "ulimit" is not a solution because it controls shell resources. But i need to control queue size before login in and starting the shell. It is needed to limit queue size for applications started before login in.
Sorry for my... (7 Replies)
Discussion started by: Vourhey
7 Replies
6. Programming
Hii can anyone pls tell how to limit the max no of message in a posix message queue. I have made changes in proc/sys/fs/mqueue/msg_max
But still whenever i try to read the value of max. message in the queue using attr.mq_curmsgs (where struct mq_attr attr) its giving the default value as 10.... (0 Replies)
Discussion started by: mohit3884
0 Replies
7. Programming
Hello,
I am trying to implement posix message queue application. I am faced with an error on the mq_receive section. It says "Message too long". I've tried couple of small tweeks, but to no result. Please do suggest any rectificaitons.
mq_send section-works successfully
#include... (2 Replies)
Discussion started by: katwalatapan
2 Replies
8. Programming
Hi all,
First of all thanks in advance for reading my post and for your heart for helping me.
I am trying to create a message queue using mq_open(name,oflags,mode_t,attr) method. But that function call is returning with an error code EFAULT. By googling it I found that it happens when there is... (10 Replies)
Discussion started by: parusasi
10 Replies
9. Programming
in a single main() function,so need signal handling. Use Posix Message Queue IPC mechanism , can ignore the priority and other linked list message,to implement the scenario:
client:Knock Knock
server:who's there
client: Eric
Server:Eric,Welcome.
client:exit
all process terminated
... (1 Reply)
Discussion started by: ouou
1 Replies
10. Programming
Hi,
I wanted to know whether the POSIX message queues are statically allocated memory by the kernel based on the parameters specified in the open or as and when we send messages, memory are allocated?
Does the kernel reserve the specified memory for the message queue irrespective of whether... (1 Reply)
Discussion started by: sumtata
1 Replies
LEARN ABOUT CENTOS
mq_unlink
MQ_UNLINK(3P) POSIX Programmer's Manual MQ_UNLINK(3P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing 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 pathname name. After a successful call to mq_unlink() with name, a
call to mq_open() with name shall fail 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 shall be postponed until all references to the message queue have been closed.
Calls to mq_open() to recreate 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 VALUE
Upon successful completion, the function shall return a value of zero. Otherwise, the named message queue shall be unchanged by this func-
tion 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.
ENAMETOOLONG
The length of the name argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.
ENOENT The named message queue does not exist.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
mq_close(), mq_open(), msgctl(), msgget(), msgrcv(), msgsnd(), the Base Definitions volume of IEEE Std 1003.1-2001, <mqueue.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .
IEEE
/The Open Group 2003 MQ_UNLINK(3P)