Calling process with pipes

[Xavier Amado <xavier blackbloodstudios com>]

I would need to execute a program (using g_spawn_async_with_pipes) and
pass it's output to a second process. I'm not sure how to use the
std_output in the above function though. Can anyone give me a simple
example to do something like, for example, ls | grep root
Thanks in advance.

Regards,
Xavier