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ULTRIX 4.2 - man page for getopt (ultrix section 3)

getopt(3)				       Library Functions Manual 				    getopt(3)

Name
       getopt - get option letter from argument vector

Syntax
       #include <stdio.h>
       int getopt (argc, argv, optstring)
       int argc;
       char **argv;
       char *optstring;

       extern char *optarg;
       extern int optind, opterr;

Description
       The  subroutine returns the next option letter in argv that matches a letter in optstring.  The optstring 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.  The optarg is set to point to the start of
       the option argument on return from

       The function places in optind the argv index of the next argument to  be  processed.   The  external  variable
       optind is automatically initialized to 1 before the first call to

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

Diagnostics
       The function prints an error message on stderr and returns a question mark (?)  when it encounters  an  option
       letter that is not included in optstring.  Setting opterr to 0 disables this error message.

Examples
       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:
       #include <stdio.h>
       main (argc, argv)
       int argc;
       char **argv;
       {
	      int c;
	      extern int optind, opterr;
	      extern char *optarg;
	      .
	      .
	      .
	      .
	      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':
			       ifile = 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)) {
	       .
	       .
	       .
       }

See Also
       getopt(1)

													    getopt(3)


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