[m-users.] Spawning external process

[Sean Charles (emacstheviking)]

I've used io.call_system/4 a few times but in the comments it says that it and call_system_return_signal/4 are marked as obsolete.

What's the preferred method now?

I wanted to be able to launch a process and capture either:

  - none of the  output
  - stdout only
  - stdout and stderr

When I use www as the page viewer for mmc-doc, it shows, for the io module.m that the next link is io.call_system but when I list all the modules, only `io` is shown.
I read the source code of io.m for half an hour and it seems that what I want to do may not be cleanly possible without maybe stealing and tweaking something like the implementation of `call_system_code`. I will see if I can downgrade my expectation and mange with what io.call_system/4 does for me, but I am still worried it's marked as deprecated.

Thanks
Sean