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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 arguments 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 contains 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 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''
     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("unknown 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, and is included in
     IEEE Std 1003.1-2008 ("POSIX.1").

BSD                            November 17, 2009                           BSD
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO | HISTORY