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GETSUBOPT(3)		    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
       command line.

       The argument optionp is a pointer to a pointer to the string.  The  ar-
       gument  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("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.

FreeBSD	15.0		       December	25, 2011		  GETSUBOPT(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=getsubopt&manpath=FreeBSD+15.0-RELEASE+and+Ports>

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