getopt(3)                  DG/UX 4.31                   getopt(3)



     NAME
          getopt - get option letter from argument vector

     SYNOPSIS
          int getopt (argc, argv, optstring)
          int argc;
          char **argv, *opstring;

          extern char *optarg;
          extern int optind, opterr;

     DESCRIPTION
          getopt returns the next option letter in argv that matches a
          letter in optstring.  It supports all the rules of the
          command syntax standard (see intro(1)).

          optstring must contain the option letters the command using
          getopt will recognize; if a letter is followed by a colon,
          the option is expected to have an argument, or group of
          arguments, which must 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 is initialized to 1
          before the first call to getopt.

          When all options have been processed (i.e., up to the first
          non-option argument), getopt returns -1.  The special option
          ``--'' may be used to delimit the end of the options; when
          it is encountered, -1 will be returned, and ``--'' will be
          skipped.

     DIAGNOSTICS
          getopt prints an error message on standard error and returns
          a question mark (?)  when it encounters an option letter not
          included in optstring or no option-argument after an option
          that expects one.  This error message may be disabled by
          setting opterr to 0.

     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 option o, which requires an
          option-argument:

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



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     getopt(3)                  DG/UX 4.31                   getopt(3)



               extern char *optarg;
               extern int optind;
               .
               .
               .
               while ((c = getopt(argc, argv, "abo:")) != -1)
                    switch (c) {
                    case 'a':
                         if (bflg)
                              errflg++;
                         else
                              aflg++;
                         break;
                    case 'b':
                         if (aflg)
                              errflg++;
                         else
                              bproc( );
                         break;
                    case 'o':
                         ofile = optarg;
                         break;
                    case '?':
                         errflg++;
                    }
               if (errflg) {
                    (void)fprintf(stderr, "usage: . . . ");
                    exit (2);
               }
               for ( ; optind < argc; optind++) {
                    if (access(argv[optind], 4)) {
               .
               .
               .
          }

     WARNING
          Although the following command syntax rule (see intro(1))
          relaxations are permitted under the current implementation,
          they should not be used because they may not be supported in
          future releases of the system.  As in the EXAMPLE section
          above, a and b are options, and the option o requires an
          option-argument:

               cmd -aboxxx file  (Rule 5 violation:  options with
                     option-arguments must not be grouped with other options)
               cmd -ab -oxxx file  (Rule 6 violation:  there must be
                     white space after an option that takes an option-argument)

     SEE ALSO
          getopts(1), intro(1) in the User's Reference for the DG/UX
          System.



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     getopt(3)                  DG/UX 4.31                   getopt(3)



     NOTE
          Changing the value of the variable optind, or calling getopt
          with different values of argv, may lead to unexpected
          results.



















































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