msg_get_queue

(PHP 4 >= 4.3.0, PHP 5)

msg_get_queue — Create or attach to a message queue

Açıklama

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

msg_get_queue() returns an id that can be used to access the System V message queue with the given key . The first call creates the message queue with the optional perms . A second call to msg_get_queue() for the same key will return a different message queue identifier, but both identifiers access the same underlying message queue.

Değiştirgeler

key: Message queue numeric ID
perms: Queue permissions. Default to 0666. If the message queue already exists, the perms will be ignored.

Dönen Değerler

Returns a resource handle that can be used to access the System V message queue.

Ayrıca Bakınız

msg_remove_queue() - Destroy a message queue
msg_receive() - Receive a message from a message queue
msg_send() - Send a message to a message queue
msg_stat_queue() - Returns information from the message queue data structure
msg_set_queue() - Set information in the message queue data structure

msg_queue_exists

ftok

Last updated: Fri, 13 Nov 2009

add a note User Contributed Notes
msg_get_queue

pail dot luo at gmail dot com
28-Feb-2009 05:22


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; 

} 

?>

david dot schueler at tel-billig dot de
17-Dec-2008 04:17


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.

martin dot velek at gmail dot com
01-Aug-2007 11:23


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']==0  &&

    $pole['msg_rtime']==0  &&

    $pole['msg_qnum']==0  &&

    $pole['msg_lspid']==0  &&

    $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";

?>

zxd at zhangxiaodong dot net
16-Dec-2004 05:55


#

# require --enable-sysvmsg configure option 

#

# see phpinfo() to find how to check

#

joeldg AT listbid.com
02-May-2003 07:10


// 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);

add a note

msg_queue_exists

ftok

Last updated: Fri, 13 Nov 2009