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author | deraadt <> | 1995-10-18 08:42:23 +0000 |
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committer | deraadt <> | 1995-10-18 08:42:23 +0000 |
commit | 0527d29da443886d92e9a418180c5b25a5f8d270 (patch) | |
tree | 86b3a64928451a669cefa27900e5884036b4e349 /src/lib/libc/stdlib/getopt.3 | |
download | openbsd-0527d29da443886d92e9a418180c5b25a5f8d270.tar.gz openbsd-0527d29da443886d92e9a418180c5b25a5f8d270.tar.bz2 openbsd-0527d29da443886d92e9a418180c5b25a5f8d270.zip |
initial import of NetBSD tree
Diffstat (limited to 'src/lib/libc/stdlib/getopt.3')
-rw-r--r-- | src/lib/libc/stdlib/getopt.3 | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/src/lib/libc/stdlib/getopt.3 b/src/lib/libc/stdlib/getopt.3 new file mode 100644 index 0000000000..f843881afd --- /dev/null +++ b/src/lib/libc/stdlib/getopt.3 | |||
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1 | .\" Copyright (c) 1988, 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 | .\" @(#)getopt.3 8.4 (Berkeley) 4/19/94 | ||
33 | .\" | ||
34 | .Dd April 19, 1994 | ||
35 | .Dt GETOPT 3 | ||
36 | .Os BSD 4.3 | ||
37 | .Sh NAME | ||
38 | .Nm getopt | ||
39 | .Nd get option character from command line argument list | ||
40 | .Sh SYNOPSIS | ||
41 | .Fd #include <unistd.h> | ||
42 | .Vt extern char *optarg; | ||
43 | .Vt extern int optind; | ||
44 | .Vt extern int optopt; | ||
45 | .Vt extern int opterr; | ||
46 | .Vt extern int optreset; | ||
47 | .Ft int | ||
48 | .Fn getopt "int argc" "char * const *argv" "const char *optstring" | ||
49 | .Sh DESCRIPTION | ||
50 | The | ||
51 | .Fn getopt | ||
52 | function incrementally parses a command line argument list | ||
53 | .Fa argv | ||
54 | and returns the next | ||
55 | .Em known | ||
56 | option character. | ||
57 | An option character is | ||
58 | .Em known | ||
59 | if it has been specified in the string of accepted option characters, | ||
60 | .Fa optstring . | ||
61 | .Pp | ||
62 | The option string | ||
63 | .Fa optstring | ||
64 | may contain the following elements: individual characters, and | ||
65 | characters followed by a colon to indicate an option argument | ||
66 | is to follow. | ||
67 | For example, an option string | ||
68 | .Li "\&""x"" | ||
69 | recognizes an option | ||
70 | .Dq Fl x , | ||
71 | and an option string | ||
72 | .Li "\&""x:"" | ||
73 | recognizes an option and argument | ||
74 | .Dq Fl x Ar argument . | ||
75 | It does not matter to | ||
76 | .Fn getopt | ||
77 | if a following argument has leading white space. | ||
78 | .Pp | ||
79 | On return from | ||
80 | .Fn getopt , | ||
81 | .Va optarg | ||
82 | points to an option argument, if it is anticipated, | ||
83 | and the variable | ||
84 | .Va optind | ||
85 | contains the index to the next | ||
86 | .Fa argv | ||
87 | argument for a subsequent call | ||
88 | to | ||
89 | .Fn getopt . | ||
90 | The variable | ||
91 | .Va optopt | ||
92 | saves the last | ||
93 | .Em known | ||
94 | option character returned by | ||
95 | .Fn getopt . | ||
96 | .Pp | ||
97 | The variable | ||
98 | .Va opterr | ||
99 | and | ||
100 | .Va optind | ||
101 | are both initialized to 1. | ||
102 | The | ||
103 | .Va optind | ||
104 | variable may be set to another value before a set of calls to | ||
105 | .Fn getopt | ||
106 | in order to skip over more or less argv entries. | ||
107 | .Pp | ||
108 | In order to use | ||
109 | .Fn getopt | ||
110 | to evaluate multiple sets of arguments, or to evaluate a single set of | ||
111 | arguments multiple times, | ||
112 | the variable | ||
113 | .Va optreset | ||
114 | must be set to 1 before the second and each additional set of calls to | ||
115 | .Fn getopt , | ||
116 | and the variable | ||
117 | .Va optind | ||
118 | must be reinitialized. | ||
119 | .Pp | ||
120 | The | ||
121 | .Fn getopt | ||
122 | function | ||
123 | returns \-1 | ||
124 | when the argument list is exhausted, or a non-recognized | ||
125 | option is encountered. | ||
126 | The interpretation of options in the argument list may be cancelled | ||
127 | by the option | ||
128 | .Ql -- | ||
129 | (double dash) which causes | ||
130 | .Fn getopt | ||
131 | to signal the end of argument processing and returns \-1. | ||
132 | When all options have been processed (i.e., up to the first non-option | ||
133 | argument), | ||
134 | .Fn getopt | ||
135 | returns \-1. | ||
136 | .Sh DIAGNOSTICS | ||
137 | If the | ||
138 | .Fn getopt | ||
139 | function encounters a character not found in the string | ||
140 | .Va optarg | ||
141 | or detects | ||
142 | a missing option argument it writes an error message and returns | ||
143 | .Ql ? | ||
144 | to the | ||
145 | .Em stderr . | ||
146 | Setting | ||
147 | .Va opterr | ||
148 | to a zero will disable these error messages. | ||
149 | If | ||
150 | .Va optstring | ||
151 | has a leading | ||
152 | .Ql \&: | ||
153 | then a missing option argument causes a | ||
154 | .Ql \&: | ||
155 | to be returned in addition to suppressing any error messages. | ||
156 | .Pp | ||
157 | Option arguments are allowed to begin with | ||
158 | .Dq Li \- ; | ||
159 | this is reasonable but | ||
160 | reduces the amount of error checking possible. | ||
161 | .Sh EXTENSIONS | ||
162 | The | ||
163 | .Va optreset | ||
164 | variable was added to make it possible to call the | ||
165 | .Fn getopt | ||
166 | function multiple times. | ||
167 | This is an extension to the | ||
168 | .St -p1003.2 | ||
169 | specification. | ||
170 | .Sh EXAMPLE | ||
171 | .Bd -literal -compact | ||
172 | extern char *optarg; | ||
173 | extern int optind; | ||
174 | int bflag, ch, fd; | ||
175 | |||
176 | bflag = 0; | ||
177 | while ((ch = getopt(argc, argv, "bf:")) != -1) | ||
178 | switch(ch) { | ||
179 | case 'b': | ||
180 | bflag = 1; | ||
181 | break; | ||
182 | case 'f': | ||
183 | if ((fd = open(optarg, O_RDONLY, 0)) < 0) { | ||
184 | (void)fprintf(stderr, | ||
185 | "myname: %s: %s\en", optarg, strerror(errno)); | ||
186 | exit(1); | ||
187 | } | ||
188 | break; | ||
189 | case '?': | ||
190 | default: | ||
191 | usage(); | ||
192 | } | ||
193 | argc -= optind; | ||
194 | argv += optind; | ||
195 | .Ed | ||
196 | .Sh HISTORY | ||
197 | The | ||
198 | .Fn getopt | ||
199 | function appeared | ||
200 | .Bx 4.3 . | ||
201 | .Sh BUGS | ||
202 | The | ||
203 | .Fn getopt | ||
204 | function was once specified to return | ||
205 | .Dv EOF | ||
206 | instead of \-1. | ||
207 | This was changed by | ||
208 | .St -p1003.2-92 | ||
209 | to decouple | ||
210 | .Fn getopt | ||
211 | from | ||
212 | .Pa <stdio.h> . | ||
213 | .Pp | ||
214 | A single dash | ||
215 | .Dq Li - | ||
216 | may be specified as an character in | ||
217 | .Fa optstring , | ||
218 | however it should | ||
219 | .Em never | ||
220 | have an argument associated with it. | ||
221 | This allows | ||
222 | .Fn getopt | ||
223 | to be used with programs that expect | ||
224 | .Dq Li - | ||
225 | as an option flag. | ||
226 | This practice is wrong, and should not be used in any current development. | ||
227 | It is provided for backward compatibility | ||
228 | .Em only . | ||
229 | By default, a single dash causes | ||
230 | .Fn getopt | ||
231 | to return \-1. | ||
232 | This is, we believe, compatible with System V. | ||
233 | .Pp | ||
234 | It is also possible to handle digits as option letters. | ||
235 | This allows | ||
236 | .Fn getopt | ||
237 | to be used with programs that expect a number | ||
238 | .Pq Dq Li \&-\&3 | ||
239 | as an option. | ||
240 | This practice is wrong, and should not be used in any current development. | ||
241 | It is provided for backward compatibility | ||
242 | .Em only . | ||
243 | The following code fragment works in most cases. | ||
244 | .Bd -literal -offset indent | ||
245 | int length; | ||
246 | char *p; | ||
247 | |||
248 | while ((c = getopt(argc, argv, "0123456789")) != -1) | ||
249 | switch (c) { | ||
250 | case '0': case '1': case '2': case '3': case '4': | ||
251 | case '5': case '6': case '7': case '8': case '9': | ||
252 | p = argv[optind - 1]; | ||
253 | if (p[0] == '-' && p[1] == ch && !p[2]) | ||
254 | length = atoi(++p); | ||
255 | else | ||
256 | length = atoi(argv[optind] + 1); | ||
257 | break; | ||
258 | } | ||
259 | } | ||
260 | .Ed | ||