xref: /freebsd/lib/libc/stdlib/getsubopt.3 (revision 2e3f49888ec8851bafb22011533217487764fdb0)
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28.Dd December 25, 2011
29.Dt GETSUBOPT 3
30.Os
31.Sh NAME
32.Nm getsubopt
33.Nd get sub options from an argument
34.Sh LIBRARY
35.Lb libc
36.Sh SYNOPSIS
37.In stdlib.h
38.Vt extern char *suboptarg ;
39.Ft int
40.Fn getsubopt "char **optionp" "char * const *tokens" "char **valuep"
41.Sh DESCRIPTION
42The
43.Fn getsubopt
44function
45parses a string containing tokens delimited by one or more tab, space or
46comma
47.Pq Ql \&,
48characters.
49It is intended for use in parsing groups of option arguments provided
50as part of a utility command line.
51.Pp
52The argument
53.Fa optionp
54is a pointer to a pointer to the string.
55The argument
56.Fa tokens
57is a pointer to a
58.Dv NULL Ns -terminated
59array of pointers to strings.
60.Pp
61The
62.Fn getsubopt
63function
64returns the zero-based offset of the pointer in the
65.Fa tokens
66array referencing a string which matches the first token
67in the string, or, \-1 if the string contains no tokens or
68.Fa tokens
69does not contain a matching string.
70.Pp
71If the token is of the form ``name=value'', the location referenced by
72.Fa valuep
73will be set to point to the start of the ``value'' portion of the token.
74.Pp
75On return from
76.Fn getsubopt ,
77.Fa optionp
78will be set to point to the start of the next token in the string,
79or the null at the end of the string if no more tokens are present.
80The external variable
81.Fa suboptarg
82will be set to point to the start of the current token, or
83.Dv NULL
84if no
85tokens were present.
86The argument
87.Fa valuep
88will be set to point to the ``value'' portion of the token, or
89.Dv NULL
90if no ``value'' portion was present.
91.Sh EXAMPLES
92.Bd -literal -compact
93char *tokens[] = {
94	#define	ONE	0
95		"one",
96	#define	TWO	1
97		"two",
98	NULL
99};
100
101\&...
102
103extern char *optarg, *suboptarg;
104char *options, *value;
105
106while ((ch = getopt(argc, argv, "ab:")) != \-1) {
107	switch(ch) {
108	case 'a':
109		/* process ``a'' option */
110		break;
111	case 'b':
112		options = optarg;
113		while (*options) {
114			switch(getsubopt(&options, tokens, &value)) {
115			case ONE:
116				/* process ``one'' sub option */
117				break;
118			case TWO:
119				/* process ``two'' sub option */
120				if (!value)
121					error("no value for two");
122				i = atoi(value);
123				break;
124			case \-1:
125				if (suboptarg)
126					error("illegal sub option %s",
127					  suboptarg);
128				else
129					error("missing sub option");
130				break;
131			}
132		}
133		break;
134	}
135}
136.Ed
137.Sh SEE ALSO
138.Xr getopt 3 ,
139.Xr strsep 3
140.Sh HISTORY
141The
142.Fn getsubopt
143function first appeared in
144.Bx 4.4 .
145