Sharing variables between child processes in PHP?
forked children will gain their own dedicated copy of their memory space as soon as they write anywhere to it - this is "copy-on-write". While shmop does provide access to a common memory location, the actual PHP variables and whatnot defined in the script are NOT shared between the children.
Doing $x = 7; in one child will not make the $x in the other children also become 7. Each child will have its own dedicated $x that is completely independent of everyone else's copy.
As long as father and children know the key/keys of the shared memory segment is ok to do a shmop_open before pcnlt_fork. But remember that pcnlt_fork returns 0 in the child's process and -1 on failure to create the child (check your code near the comment /confusion/). The father will have in $pid the PID of the child process just created.
Check it here:
Use this class:http://pastebin.com/0wnxh4gY
http://framework.zend.com/manual/1.7/en/zendx.console.process.unix.overview.html
It utilizes shm functions to share variables across many processes with the setVariable method...obviously you shoud use it running PHP in some kind of cgi mode most likely php-fpm