GETOPT(3)          UNIX 5.0 (21 January 1986)           GETOPT(3)


     NAME

          getopt, optarg, optind - get option letter from argv

     SYNOPSIS

          int getopt(argc, argv, opts)
          int argc;
          char **argv;
          char *opts;

          int
          getarg(nargc, nargv)
          int nargc;
          char *nargv[];

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

     DESCRIPTION

          This is the public domain getopt from AT&T with enhancements.

          Getopt returns the next option letter in argv that matches a
          letter in opts. Opts is a string of recognized option
          letters; if a letter is followed by a colon, the option is
          expected to have an argument that may or may not be
          separated from it by white space.  Optarg is set to point to
          the start of the option argument on return from getopt.

          Getopt places in optind the argv index of the next argument
          to be processed.  Optind is external and it is normally
          initialized to one automatically before the first call to
          getopt. This is so that the program name will not be processed
          as an argument if getopt is used to process the command line
          passed to the main function of a program.

          When all options have been processed (i.e., up to the first
          non-option argument), getopt returns EOF. The special option
          -- may be used to delimit the end of the options; EOF will
          be returned, and -- will be skipped.


          Getarg returns the index of the next argument, or EOF if the
          argument string is exhausted.  Getarg is used to get the file
          arguments after getopt() is finished.  Getarg updates optarg
          to point at the argument, and increments optind to point
          at the next argument.



     GETOPT(3)          UNIX 5.0 (21 January 1986)           GETOPT(3)


     DIAGNOSTICS

          Getopt prints an error message on stderr (if opterr is non-
          zero) and returns a question mark (?) when it encounters an
          option letter not included in opts. The error message uses
          argv[0] as the program name.  If this is not desireable, set
          opterr = 0 and issue your own error message when getopt
          returns '?'.

     EXAMPLE

          The following code fragment shows how one might process the
          arguments for a command that can take the mutually exclusive
          options a and b, and the options f and o, both of which
          require arguments:

               main(argc, argv)
               int argc;
               char **argv;
               {
                    int c;
                    extern int optind;
                    extern char *optarg;

                    ...



     GETOPT(3)          UNIX 5.0 (21 January 1986)           GETOPT(3)


                    while ((c = getopt(argc, argv, "abf:o:")) != EOF)
                         switch (c) {

                         case 'a':
                              if (bflg)
                                   errflg++;
                              else
                                   aflg++;
                              break;

                         case 'b':
                              if (aflg)
                                   errflg++;
                              else
                                   bproc();
                              break;

                         case 'f':
                              infile = optarg;
                              break;

                         case 'o':
                              ofile = optarg;
                              bufsiza = 512;
                              break;

                         case '?':
                              errflg++;
                         }

                    if (errflg) {
                         fprintf(stderr, "usage: . . . ");
                         exit(2);
                    }

                    for (; optind < argc; optind++) {

                         if (access(argv[optind], 4)) {

                              ...
                         }
                   }