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Description

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 (default: 0666). 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. If the message queue already exists, the perms will be ignored.

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msg_get_queue

martin dot velek at gmail dot com
01-Aug-2007 04:23


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
15-Dec-2004 09:55


#

# require --enable-sysvmsg configure option 

#

# see phpinfo() to find how to check

#

joeldg AT listbid.com
02-May-2003 12:10


// 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);

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