msg_queue_exists()

(PHP 5 >= 5.3.0, PHP 7)

Check whether a message queue exists

说明

msg_queue_exists(int $key): bool

Checks whether the message queue$keyexists.

参数

$key

Queue key.

返回值

成功时返回TRUE，或者在失败时返回FALSE。

参见

• msg_remove_queue()Destroy a message queue
• msg_receive()Receive a message from a message queue
• msg_stat_queue()Returns information from the message queue data structure

A simple script for checking what message queues are in use on a [presumably new] server environment.
Run with php-cli
<?php
$k = 0;
while (true) {
 echo $key,"...\r";
 if (msg_queue_exists($key))
  echo "\r",$key,'::Exists',"\n";
  $key++;
}
?>

This function is creating new queue (and returning true) if you set NULL into $key variable.
<?php 
$isQueueCreated = msg_queue_exists(NULL); 
print $isQueueCreated ? "WTF??!" : "ok, everything is fine..";
?>
WTF??!
# ipcs -q
0x00000000 173047808 root    0    0      0

A workaround for those not yet running 5.3 on *nix:
<?php
function queue_exists($key) {
  if(function_exists("msg_queue_exists")) {
    return msg_queue_exists($key);
  } else {
    $aQueues = array();
    exec("ipcs -q | grep \"^[0-9]\" | cut -d \" \" -f 1", $aQueues);
    if(in_array($key,$aQueues)) return true;
    else return false;
  }
}
?>
Maybe a bit slow and kludgey, but it works.

Following code will do the job:
<?php
$key = 0;
while (true) {
 echo $key,"...\r";
 if (msg_queue_exists($key))
  echo "\r",$key,'::Exists',"\n";
  $key++;
}
?>