4.4BSD/usr/share/man/cat3/getsubopt.0

GETSUBOPT(3)                BSD Programmer's Manual               GETSUBOPT(3)

NNAAMMEE
     ggeettssuubboopptt - get sub options from an argument

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<ssttddlliibb..hh>>

     _e_x_t_e_r_n _c_h_a_r _*_s_u_b_o_p_t_a_r_g

     _i_n_t
     ggeettssuubboopptt(_c_h_a_r _*_*_o_p_t_i_o_n_p, _c_h_a_r _* _c_o_n_s_t _*_t_o_k_e_n_s, _c_h_a_r _*_*_v_a_l_u_e_p);

DDEESSCCRRIIPPTTIIOONN
     The ggeettssuubboopptt() function parses a string containing tokens delimited by
     one or more tab, space or comma (`,') characters.  It is intended for use
     in parsing groups of option arguments provided as part of a utility com-
     mand line.

     The argument _o_p_t_i_o_n_p is a pointer to a pointer to the string.  The argu-
     ment _t_o_k_e_n_s is a pointer to a NULL-terminated array of pointers to
     strings.

     The ggeettssuubboopptt() function returns the zero-based offset of the pointer in
     the _t_o_k_e_n_s array referencing a string which matches the first token in
     the string, or, -1 if the string contains no tokens or _t_o_k_e_n_s does not
     contain a matching string.

     If the token is of the form ``name=value'', the location referenced by
     _v_a_l_u_e_p will be set to point to the start of the ``value'' portion of the
     token.

     On return from ggeettssuubboopptt(), _o_p_t_i_o_n_p will be set to point to the start of
     the next token in the string, or the null at the end of the string if no
     more tokens are present.  The external variable _s_u_b_o_p_t_a_r_g will be set to
     point to the start of the current token, or NULL if no tokens were pre-
     sent.  The argument _v_a_l_u_e_p will be set to point to the ``value'' portion
     of the token, or NULL if no ``value'' portion was present.

EEXXAAMMPPLLEE
     char *tokens[] = {
             #define ONE     0
                     "one",
             #define TWO     1
                     "two",
             NULL
     };

     ...

     extern char *optarg, *suboptarg;
     char *options, *value;

     while ((ch = getopt(argc, argv, "ab:")) != -1) {
             switch(ch) {
             case 'a':
                     /* process ``a'' option */
                     break;
             case 'b':
                     options = optarg;
                     while (*options) {
                             switch(getsubopt(&options, tokens, &value)) {
                             case ONE:
                                     /* process ``one'' sub option */
                                     break;
                             case TWO:
                                     /* process ``two'' sub option */
                                     if (!value)
                                             error("no value for two");
                                     i = atoi(value);
                                     break;
                             case -1:
                                     if (suboptarg)
                                             error("illegal sub option %s",
                                               suboptarg);
                                     else
                                             error("missing sub option");
                                     break;
                     }
                     break;
             }

SSEEEE AALLSSOO
     getopt(3),  strsep(3)

HHIISSTTOORRYY
     The ggeettssuubboopptt() function first appeared in 4.4BSD.

4.4BSD                           June 9, 1993                                2