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I have never ever done IPC before (that I know of :) ). Lets say I have a program that spawns 2 children.

One of the children listens on a socket for data from a server (AF_INET, DGRAM).

The other child watches a log (using the tail -f concept -- does NOT use system(tail...)) that gets continually written to.

The main module (daemonized already) spawns these two kiddies off. It will react to the work they perform.

Now, since the child processes fork(), I still have to keep them in a loop to watch what they spit out, right? ...thing is is that I would then have two different loops of which neither are really related to each other so I don't want to nest the loops that they are in. Am I correct?

eg.

This will not work because the second loop won't get used until the first one is over which means that it will never get called...

main:

  fork(child1);
  fork(child2);
  
  # endless loop until signal caught from
  # shell (child1):
  loop(read from child1) {
      react
  }

  # endless loop until signal caught from
  # shell (child2):
  loop(read from child2) {
      react
  }

main END:
[download]

This next loop will not work because the innermost loop will be the only loop running so the outer loop will never get munched on.

main:

  fork(child1);
  fork(child2);
  
  # endless loop until signal caught from
  # shell (child1):
  loop(read from child1) {
      react
      # endless loop until signal caught from
      # shell (child2):
      loop(read from child2) {
          react
      }
  }

main END:
[download]

I have to be able to do something like this:

main:


  fork(child1);
  fork(child2);
  
  # endless loop until signal caught from
  # shell (child1):
  loop(true) {
      check child1  # call sub reacting from input;
      check child2  # call sub reacting from input;
  }                 # loop until a signal is caught.

END main:
[download]

How would this be done? I have read through the Perl cookbook on IPC and I can't seem to pick up how I would do something like this using the information provided in their examples and documentation. I have read perldoc perlipc but I admit that I am so new to this stuff that a lot of it is jargon that is over my head.

I have already written the meat of the three modules. This is the biggest part that stumps me.

I think what I really need is some documentation that doesn't talk above my head :( One of these days I will understand the high-talk but I have the terrible problem where I can get lost in the words very quickly. If anyone has a site or something out there that is easily read I would love that. I also learn quite quickly from source code. If there is some code out there that would give me an idea of how to do what I am trying to do that would be very helpful as well.

Thanks guys.

----------
- Jim

In reply to A challenge...at least for me. by snafu

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