VMS Help CC, Run-time functions, getopt  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The getopt function is a command-line parser that can be used by
  applications that follow Utility Syntax Guidelines 3,4,5,6,7,9, and
  10 in Section 10.2 of the XBD specification.  The remaining
  guidelines are not addressed by getopt and are the responsibility
  of the application.

  Syntax:

       #include <unistd.h> (X/Open, POSIX-2)

       #include <stdio.h> (X/Open, POSIX-1)

       int getopt(int argc, char * const argv[], const char
       *optstring);

       extern char *optarg;
       extern int optind, opterr, optopt;