A minimal POSIX getopt() ANSI C header library

This is a small, drop-in, header library that precisely implements the bare minimum of POSIX getopt(3). It provides basic option parsing for non-POSIX systems without the need to adapt or change existing programs. For a more feature-rich portable option parsing library, see Optparse.

Exactly one common extension is supported: Setting optind to 0 will reset the option parser for its next run. This was primarily added in support of testing.