fopen failed to open pipe file in Linux+Apache environment

["mike xu" <clumsguy@xxxxxxxxx>]

Hi, I have problem of open named pipe file in linux.

Here is my sample code:

 $fifo_file = "/dev/pmsg";
 @ $fp = fopen($fifo_file, 'w+b');
 if(!$fp) {
   echo "open ".$fifo_file." failed";
 }
 else {
   $msg_cmd = "ttttttt";
   fwrite($fp, $msg_cmd, strlen($msg_cmd));
   fclose($fp);
 }

There is an other program which is waiting for messages from /dev/pmsg
forever. You could also test it by running `cat /dev/pmsg` in shell console.
Every one have permissions of read and write for /dev/pmsg
prw-rw-rw- 1 root root 0 12-08 10:13 /dev/pmsg

Environment info: php-5.1.2-5, httpd-2.2.0-5.1.2, OS: Redhat FC5

Thanks in advance,
Mike