This is the popt command line option parsing library. While it is similiar to getopt(3), it contains a number of enhancements, including: 1) popt is fully reentrant 2) popt can parse arbitrary argv[] style arrays while getopt(2) makes this quite difficult 3) popt allows users to alias command line arguments 4) popt provides convience functions for parsing strings into argv[] style arrays WWW: http://freshmeat.net/projects/popt/