msg_get_queue

(PHP 4 >= 4.3.0, PHP 5)

msg_get_queueCrée ou s'attache à une file de messages

Description

resource msg_get_queue ( int $key [, int $perms = 0666 ] )

msg_get_queue() retourne une ressource qui peut être utilisée avec les files de messages System V et la clé key. Le premier appel à la fonction va créer la file de messages, avec les droits optionnels de perms. Un second appel à msg_get_queue() avec la même clé key retournera une autre ressource de file de messages, mais les deux identifiants aboutissent à la même file de messages.

Liste de paramètres

key

Identifiant numérique du message dans la file

perms

Permission dans la file. Par défaut, vaut 0666. Si la file de messages existe déjà, le paramètre perms sera ignoré.

Valeurs de retour

Retourne une ressource qui peut être utilisée pour accéder à la file de messages System V.

Voir aussi

add a note add a note

User Contributed Notes 6 notes

up
1
Michael Iatrou
4 years ago
If you are getting the following message (on Linux):

Warning: msg_get_queue() [function.msg-get-queue]: failed for key 0x12345678: No space left on device in /path/to/script.php on line 1

aside from what [others have] suggested, you should also check and set an appropriate value for kernel parameter kernel.msgmni, e.g. sysctl -w kernel.msgmni=256
up
0
david dot schueler at tel-billig dot de
5 years ago
If you are getting this message on your *NIX box:

Warning: msg_get_queue() [function.msg-get-queue]: failed for key 0x12345678: No space left on device in /path/to/script.php on line 1

you may use the command "ipcrm" as root to clear the message queue. Use "man ipcrm" to get more info on it.
The default setting for maximum messages in the queue is stored in /proc/sys/fs/mqueue/msg_max. To increase it to a maximum of 100 messages, just run:
echo 100 > /proc/sys/fs/mqueue/msg_max

Please ensure to follow a good programming style and close/free all your message queues before your script exits to avoid those warning messages.
up
0
martin dot velek at gmail dot com
6 years ago
Lack of IPC_EXCL makes me unhappy. Of course, you can use ftok() to generate a unique key. This code is not allmighty, another process under the same user can open the queue and function returns true. But in some situation it could help.

code:

<?
function ipcEXCL($res,$perm)
{
$pole = msg_stat_queue($res);

if(
$pole['msg_perm.uid']==posix_getuid() &&
   
$pole['msg_perm.gid']==posix_getgid()  &&
   
$pole['msg_perm.mode']==$perm  &&
   
$pole['msg_stime']==&&
   
$pole['msg_rtime']==&&
   
$pole['msg_qnum']==&&
   
$pole['msg_lspid']==&&
   
$pole['msg_rspid']==0)
        return
true;
else
        return
false;
}

$res=msg_get_queue($key,$perm);

if(
ipcEXCL($res,$perm))
   echo
"probably I am a creator:";
else
   echo
"probably not";
?>
up
0
joeldg AT listbid.com
11 years ago
// Here is an example of working with message queues.
// if you have forked processes, this could be a great way of passing
// out work to them

// create the message queue
// pick a file..
  $key_t = msg_get_queue(ftok("/tmp/php_msgqueue.stat", 'R'),0666 | IPC_CREAT);

    // place two messages on the queue
    if (!msg_send ($key_t, 1, 'This is message #1', true, true, $msg_err))
       echo "Msg not sent because $msg_err\n";
    if (!msg_send ($key_t, 1, 'This is message #2 ', true, true, $msg_err))
       echo "Msg not sent because $msg_err\n";
     
    // lets look at the queue structure 'msg_qnum' is really what we want to see
    // it should be '2'
    print_r(msg_stat_queue($key_t));
   
    // pull off the stack
        if (msg_receive ($key_t, 1, $msg_type, 16384, $msg, true, 0, $msg_error)) {
           if ($msg == 'Quit');
           echo "$msg\n"; // prints 'This is message #1'
        } else {
           echo "Received $msg_error fetching message\n";
        }
    // look at the structure again, ms_qnum should be '1'   
    print_r(msg_stat_queue($key_t));
        if (msg_receive ($key_t, 1, $msg_type, 16384, $msg, true, 0, $msg_error)) {
           if ($msg == 'Quit');
           echo "$msg\n"; // prints 'This is message #2'
        } else {
           echo "Received $msg_error fetching message\n";
        }
   // look at the structure again, ms_qnum should be '0', no more messages on the queue
   print_r(msg_stat_queue($key_t)); 

   // get rid of the queue we created
   msg_remove_queue ($key_t);
up
-1
Morten Brrup
4 years ago
IPC_CREAT has no effect in this function. The PHP source code (file sysvmsg.c) reveals that only if msgget(key,0) fails, msgget(key, IPC_CREAT | IPC_EXCL | perms) is used.
up
-1
pail dot luo at gmail dot com
5 years ago
A simple Sample to introduce Message Queue.

<?php
if ( sizeof($argv)<2 ) {
        echo
"Usage: $argv[0] stat|send|receive|remove msgType MSG [msg] \n\n" ;
        echo
"   EX: $argv[0] send 1 \"This is no 1\" \n" ;
        echo
"       $argv[0] receive ID \n" ;
        echo
"       $argv[0] stat \n" ;
        echo
"       $argv[0] remove \n" ;
        exit;
}

$MSGKey = "123456" ;

## Create or attach to a message queue
$seg = msg_get_queue($MSGKey) ;

switch (
$argv[1] ) {
    case
"send":
       
msg_send($seg, $argv[2], $argv[3]);
        echo
"msg_send done...\n" ;
        break;
       
    case
"receive":
       
$stat = msg_stat_queue( $seg );
        echo
'Messages in the queue: '.$stat['msg_qnum']."\n";
        if (
$stat['msg_qnum']>0 ) {
           
msg_receive($seg, $argv[2], $msgtype, 1024, $data);
           
var_dump($msgtype);
           
var_dump($data);
            echo
"\n";
        }
        else {
            echo
"No Msg...\n";
        }
        break;
   
    case
"stat":
     
print_r( msg_stat_queue($seg) );
        break;
       
    case
"remove":
       
msg_remove_queue($seg);
        break;
}
?>
To Top