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GETSUBOPT(3)                       BSD Library Functions Manual                      GETSUBOPT(3)

NAME
     getsubopt -- get sub options from an argument

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     extern char *suboptarg;

     int
     getsubopt(char **optionp, char * const *tokens, char **valuep);

DESCRIPTION
     The getsubopt() 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 argu-
     ments provided as part of a utility command line.

     The argument optionp is a pointer to a pointer to the string.  The argument tokens is a
     pointer to a NULL-terminated array of pointers to strings.

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

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

     On return from getsubopt(), optionp 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 exter-
     nal variable suboptarg will be set to point to the start of the current token, or NULL if no
     tokens were present.  The argument valuep will be set to point to the ``value'' portion of
     the token, or NULL if no ``value'' portion was present.

EXAMPLES
     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;
             }

SEE ALSO
     getopt(3), strsep(3)

HISTORY
     The getsubopt() function first appeared in 4.4BSD.

BSD                                        June 9, 1993                                       BSD