usr/src/lib/libc/stdlib/getsubopt.3

.\" Copyright (c) 1990 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)getsubopt.3 5.2 (Berkeley) %G%
.\"
.TH GETSUBOPT 3 ""
.UC 7
.SH NAME
getsubopt \- get sub options from an argument
.SH SYNOPSIS
.nf
.ft B
int getsubopt(char **optionp, char * const *tokens, char **valuep);

extern char *suboptarg;
.SH DESCRIPTION
.I Getsubopt
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.
.PP
.I Optionp
is a pointer to a pointer to the string.
.I Tokens
is a pointer to a NULL-terminated array of pointers to strings.
.PP
.I Getsubopt
returns the zero-based offset of the pointer in the
.I tokens
array referencing a string which matches the first token
in the string, or, -1 if the string contains no tokens or
.I tokens
does not contain a matching string.
.PP
If the token is of the form ``name=value'', the location referenced by
.I valuep
will be set to point to the start of the ``value'' portion of the token.
.PP
On return from
.IR getsubopt ,
.I 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
.I suboptarg
will be set to point to the start of the current token, or NULL if no
tokens were present.
.I Valuep
will be set to point to the ``value'' portion of the token, or NULL
if no ``value'' portion was present.
.SH EXAMPLE
.nf
.RS
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;
        }
.fi
.SH SEE\ ALSO
getopt(3), strsep(3)