Question

So I want to be able to do the following in PHP. From the command line I call a script.

 /usr/bin/php mychildren.php

I want the script to be able to create 2 child processes both of which stay active indefinitely. (say we make them infinite loops =D), but I want the child processes to occasionally to echo out hello for the 1st process and goodbye for the second process. And then when I do a signal interrupt (ctrl+c) using pcntl_signal I can then kill the 2 child processes and once I have verification that they are killed then I kill the parent process.

Is this even possible?! I looked through streaming a little and I am super confuzzled as to how to get this working. Seems like it should work, but I can’t get anything to work properly.

Quick details:
2 child processes
each child processes occasionally echos something random
when I kill the parent the children die, and once they are dead then the parent dies

Answer 1

While you can use pcntl_fork to create subprocesses, oftentimes it is better to execute the subprocesses anew with proc_open. Use pcntl_signal to install signal handlers (to kill the subprocesses). If you want the child processes to directly write to the same output, you’ll have to implement some kind of IPC to avoid both writing at the same time.

Therefore, it’s probably better to let both subprocesses write to the main process, and let the main process wait for full lines or otherwise synchronize outputs.