xref: /freebsd/lib/libc/stdlib/getsubopt.3 (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
1.\" Copyright (c) 1990, 1991, 1993
2.\"	The Regents of the University of California.  All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\"    notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\"    notice, this list of conditions and the following disclaimer in the
11.\"    documentation and/or other materials provided with the distribution.
12.\" 3. All advertising materials mentioning features or use of this software
13.\"    must display the following acknowledgement:
14.\"	This product includes software developed by the University of
15.\"	California, Berkeley and its contributors.
16.\" 4. Neither the name of the University nor the names of its contributors
17.\"    may be used to endorse or promote products derived from this software
18.\"    without specific prior written permission.
19.\"
20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30.\" SUCH DAMAGE.
31.\"
32.\"     @(#)getsubopt.3	8.1 (Berkeley) 6/9/93
33.\" $FreeBSD$
34.\"
35.Dd June 9, 1993
36.Dt GETSUBOPT 3
37.Os
38.Sh NAME
39.Nm getsubopt
40.Nd get sub options from an argument
41.Sh SYNOPSIS
42.Fd #include <unistd.h>
43.Vt extern char *suboptarg
44.Ft int
45.Fn getsubopt "char **optionp" "char * const *tokens" "char **valuep"
46.Sh DESCRIPTION
47The
48.Fn getsubopt
49function
50parses a string containing tokens delimited by one or more tab, space or
51comma
52.Pq Ql \&,
53characters.
54It is intended for use in parsing groups of option arguments provided
55as part of a utility command line.
56.Pp
57The argument
58.Fa optionp
59is a pointer to a pointer to the string.
60The argument
61.Fa tokens
62is a pointer to a
63.Dv NULL Ns -terminated
64array of pointers to strings.
65.Pp
66The
67.Fn getsubopt
68function
69returns the zero-based offset of the pointer in the
70.Fa tokens
71array referencing a string which matches the first token
72in the string, or, \-1 if the string contains no tokens or
73.Fa tokens
74does not contain a matching string.
75.Pp
76If the token is of the form ``name=value'', the location referenced by
77.Fa valuep
78will be set to point to the start of the ``value'' portion of the token.
79.Pp
80On return from
81.Fn getsubopt ,
82.Fa optionp
83will be set to point to the start of the next token in the string,
84or the null at the end of the string if no more tokens are present.
85The external variable
86.Fa suboptarg
87will be set to point to the start of the current token, or
88.Dv NULL
89if no
90tokens were present.
91The argument
92.Fa valuep
93will be set to point to the ``value'' portion of the token, or
94.Dv NULL
95if no ``value'' portion was present.
96.Sh EXAMPLE
97.Bd -literal -compact
98char *tokens[] = {
99	#define	ONE	0
100		"one",
101	#define	TWO	1
102		"two",
103	NULL
104};
105
106\&...
107
108extern char *optarg, *suboptarg;
109char *options, *value;
110
111while ((ch = getopt(argc, argv, "ab:")) != \-1) {
112	switch(ch) {
113	case 'a':
114		/* process ``a'' option */
115		break;
116	case 'b':
117		options = optarg;
118		while (*options) {
119			switch(getsubopt(&options, tokens, &value)) {
120			case ONE:
121				/* process ``one'' sub option */
122				break;
123			case TWO:
124				/* process ``two'' sub option */
125				if (!value)
126					error("no value for two");
127				i = atoi(value);
128				break;
129			case \-1:
130				if (suboptarg)
131					error("illegal sub option %s",
132					  suboptarg);
133				else
134					error("missing sub option");
135				break;
136		}
137		break;
138	}
139.Ed
140.Sh SEE ALSO
141.Xr getopt 3 ,
142.Xr strsep 3
143.Sh HISTORY
144The
145.Fn getsubopt
146function first appeared in
147.Bx 4.4 .
148