|
|
Sponsored Content
Top Forums
Programming
creating a message queue using mq_open
Post 302470734 by parusasi on Thursday 11th of November 2010 02:44:24 AM
11-11-2010
|
|
10 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
Hi,
I am working closly with unix message queues i have encountered the following -
after creating the Q and start working with it (pushing & pulling) i receive the following stange parameters on the q's -
STIME=no_entry
Qnum=0
CBYTES=4140
when this happens, the Q is disabled (meaning i... (3 Replies)
Discussion started by: kel
3 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. Programming
hi all...
ive been trying this program where i spawn 4 threads... and i am trying to use message queue to send msgs from 3 of the threads to the parent thread... but it doent seem to be working... ive almost pulled out my hair tryin to fix the prob :confused:
another wierd thing... (1 Reply)
Discussion started by: strider
1 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. Programming
hello,
I had to implement a message queue application....between 30 processes......
all 30 proceses are getting data from serial port....
And here is THE FLOW::::::::1 connector process...which is linked with message queue to all the 30 applications. Processes get the data from serial port and... (9 Replies)
Discussion started by: arunchaudhary19
9 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 have a simple question but i can't find the answer anywhere hope to meet it here.
Why it is a bad idea to pass pointers through message queues ?
Most structs i see all of their char types are arrays... Is it becase having pointers means we could possibily send wrong bytes ?
For... (2 Replies)
Discussion started by: qlyine
2 Replies
8. Ubuntu
Hello
How can I see the created message queues in the system? (4 Replies)
Discussion started by: xyzt
4 Replies
9. Programming
Hi guys.
i have wrote a simple program to test message queue attributes. here it is:
#include <stdio.h>
#include <stdlib.h>
#include <mqueue.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
int main()
{
struct mq_attr attr;
mqd_t mqd;
... (2 Replies)
Discussion started by: majid.merkava
2 Replies
10. Programming
hello, I try to test the POSIX mq_open function on book unp like below:
#include "unpipc.h"
# include <mqueue.h>
int main(int argc, char **argv)
{
int c, flags;
mqd_t mqd;
flags = O_RDWR | O_CREAT;
while ((c = getopt(argc, argv, "e")) != -1) {
... (3 Replies)
Discussion started by: anpufeng
3 Replies
LEARN ABOUT LINUX
umask
UMASK(2) Linux Programmer's Manual UMASK(2) NAME
umask - set file mode creation mask SYNOPSIS
#include <sys/types.h> #include <sys/stat.h> mode_t umask(mode_t mask); DESCRIPTION
umask() sets the calling process's file mode creation mask (umask) to mask & 0777 (i.e., only the file permission bits of mask are used), and returns the previous value of the mask. The umask is used by open(2), mkdir(2), and other system calls that create files to modify the permissions placed on newly created files or directories. Specifically, permissions in the umask are turned off from the mode argument to open(2) and mkdir(2). The constants that should be used to specify mask are described under stat(2). The typical default value for the process umask is S_IWGRP | S_IWOTH (octal 022). In the usual case where the mode argument to open(2) is specified as: S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH (octal 0666) when creating a new file, the permissions on the resulting file will be: S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH (because 0666 & ~022 = 0644; i.e., rw-r--r--). RETURN VALUE
This system call always succeeds and the previous value of the mask is returned. CONFORMING TO
SVr4, 4.3BSD, POSIX.1-2001. NOTES
A child process created via fork(2) inherits its parent's umask. The umask is left unchanged by execve(2). The umask setting also affects the permissions assigned to POSIX IPC objects (mq_open(3), sem_open(3), shm_open(3)), FIFOs (mkfifo(3)), and Unix domain sockets (unix(7)) created by the process. The umask does not affect the permissions assigned to System V IPC objects created by the process (using msgget(2), semget(2), shmget(2)). SEE ALSO
chmod(2), mkdir(2), open(2), stat(2) COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2008-01-09 UMASK(2)