ftok
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
msg_get_queue
(PHP 4 >= 4.3.0, PHP 5)
msg_get_queue — Crea, o si collega ad una coda di messaggi
Descrizione
resource msg_get_queue
( int
$chiave
[, int $permessi
] )
La funzione msg_get_queue() restituisce un id che può essere utilizzato
per accedere alla coda dei messaggi System V con la data
chiave. La prima chiamata crea la coda dei messaggi con
i permessi indicati da permessi (default: 0666).
La seconda chiamata alla funzione msg_get_queue() per la medesima
chiave restituirà un identificatore di coda di messaggi
differente, ma entrambi accederanno alla medesima coda
di messaggi.
Se la coda dei messaggi esiste già, il parametro permessi
sarà ignorato.
Vedere anche: msg_remove_queue(), msg_receive(), msg_send(), msg_stat_queue() e msg_set_queue().
add a note
User Contributed Notes
msg_get_queue - [6 notes]
Michael Iatrou ¶
2 years ago
Morten Brrup ¶
3 years ago
IPC_CREAT has no effect in this function. The PHP source code (file sysvmsg.c) reveals that only if msgget(key,0) fails, msgget(key, IPC_CREAT | IPC_EXCL | perms) is used.
pail dot luo at gmail dot com ¶
4 years ago
A simple Sample to introduce Message Queue.
<?php
if ( sizeof($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($seg);
break;
}
?>
david dot schueler at tel-billig dot de ¶
4 years ago
If you are getting this message on your *NIX box:
Warning: msg_get_queue() [function.msg-get-queue]: failed for key 0x12345678: No space left on device in /path/to/script.php on line 1
you may use the command "ipcrm" as root to clear the message queue. Use "man ipcrm" to get more info on it.
The default setting for maximum messages in the queue is stored in /proc/sys/fs/mqueue/msg_max. To increase it to a maximum of 100 messages, just run:
echo 100 > /proc/sys/fs/mqueue/msg_max
Please ensure to follow a good programming style and close/free all your message queues before your script exits to avoid those warning messages.
martin dot velek at gmail dot com ¶
5 years ago
Lack of IPC_EXCL makes me unhappy. Of course, you can use ftok() to generate a unique key. This code is not allmighty, another process under the same user can open the queue and function returns true. But in some situation it could help.
code:
<?
function ipcEXCL($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']==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";
?>
joeldg AT listbid.com ¶
10 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);