GETOPT(3C)          UNIX Programmer's Manual           GETOPT(3C)

NAME
     getopt, optarg, optind, opterr - get option letter from argv

SYNOPSIS
     int getopt (argc, argv, optstring)
     int argc;
     char **argv, *optstring;
     extern char *optarg;
     extern int optind, opterr;

HP-UX COMPATIBILITY
     Level:    HP-UX/RUN ONLY

     Origin:   System III

DESCRIPTION
     _G_e_t_o_p_t returns the next option letter in _a_r_g_v (starting from
     _a_r_g_v[_1]) that matches a letter in _o_p_t_s_t_r_i_n_g.  _O_p_t_s_t_r_i_n_g 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.   _O_p_t_a_r_g
     is  set  to  point  to  the  start of the option argument on
     return from _g_e_t_o_p_t.

     _G_e_t_o_p_t places in _o_p_t_i_n_d the _a_r_g_v index of the next  argument
     to be processed.  _O_p_t_i_n_d is initialized to one automatically
     before the first call to _g_e_t_o_p_t.

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

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;
8               .
               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);
               }
               .
          }

DIAGNOSTICS
     _G_e_t_o_p_t prints an error message on _s_t_d_e_r_r and returns a ques-
     tion  mark  (?)  when  it  encounters  an  option letter not
     included in _o_p_t_s_t_r_i_n_g.  The error message may be  suppressed
     by setting _o_p_t_e_r_r to zero.

BUGS
     Options can be any ASCII characters except colon (:),  ques-
     tion  mark  (?),  or null (\0).  It is impossible to distin-
     guish between a ? used as a legal option, and the  character
     that  _g_e_t_o_p_t  returns  when  it encounters an invalid option
     character in the input.