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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 <stdlib.h>

     extern char *suboptarg;

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


DESCRIPTION

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

     The argument optionp is a pointer to a pointer to the string.  The argu-
     ment keylistp 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 keylistp array, referencing a string which matches the first token in
     the string
      or -1 if the string contains no tokens or keylistp 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 external 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'' por-
     tion of the token, or NULL if no ``value'' portion was present.


EXAMPLES

     char *keylistp[] = {
             #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, keylistp, &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

Mac OS X 10.8 - Generated Tue Aug 28 05:40:38 CDT 2012
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