getsubopt(3) - NetBSD Manual Pages

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GETSUBOPT(3)            NetBSD 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 *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 com-
     mand line.

     The argument optionp is a pointer to a pointer to the string.  The argu-
     ment 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'' por-
     tion 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'').

NetBSD 10.1                     August 15, 2018                    NetBSD 10.1