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.\"     @(#)getsubopt.3 8.1 (Berkeley) 6/9/93

.\" $FreeBSD: src/lib/libc/stdlib/getsubopt.3,v 1.9 2001/09/07 14:46:35 asmodai Exp $

.\"

.Dd June 9, 1993

.Dt GETSUBOPT 3

.Os

.Sh NAME

.Nm getsubopt

.Nd get sub options from an argument

.Sh LIBRARY

.Lb libc

.Sh SYNOPSIS

.In unistd.h

.Vt extern char *suboptarg ;

.Ft int

.Fn getsubopt "char **optionp" "char * const *tokens" "char **valuep"

.Sh DESCRIPTION

The

.Fn getsubopt

function

parses a string containing tokens delimited by one or more tab, space or

comma

.Pq Ql \&,

characters.

It is intended for use in parsing groups of option arguments provided

as part of a utility command line.

.Pp

The argument

.Fa optionp

is a pointer to a pointer to the string.

The argument

.Fa tokens

is a pointer to a

.Dv NULL Ns -terminated

array of pointers to strings.

.Pp

The

.Fn getsubopt

function

returns the zero-based offset of the pointer in the

.Fa tokens

array referencing a string which matches the first token

in the string, or, \-1 if the string contains no tokens or

.Fa tokens

does not contain a matching string.

.Pp

If the token is of the form ``name=value'', the location referenced by

.Fa valuep

will be set to point to the start of the ``value'' portion of the token.

.Pp

On return from

.Fn getsubopt ,

.Fa 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

.Fa suboptarg

will be set to point to the start of the current token, or

.Dv NULL

if no

tokens were present.

The argument

.Fa valuep

will be set to point to the ``value'' portion of the token, or

.Dv NULL

if no ``value'' portion was present.

.Sh EXAMPLES

.Bd -literal -compact

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;

        }

.Ed

.Sh SEE ALSO

.Xr getopt 3 ,

.Xr strsep 3

.Sh HISTORY

The

.Fn getsubopt

function first appeared in

.Bx 4.4 .