help spawning/executing a command line utility

[Jeffrey Holle]

I'm using gcc v4.0.1 on Ubuntu Linux.

I want to incorporate calls to command line utilities in my C++ for test 
purposes.  These utilities require parameters, but return no information 
to my C++ program.

I can't find the proper function to use.  spawn/execute/pexecute?

All I've found in my /usr/include directory is spawn.h, and it includes 
a bunch of functions starting with posix_.  Before I start playing 
around with these "undocumented" functions, could somebody:

  - tell me the easiest way.
  - the necessary library to link to.
  - where any online documentation is located at?