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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. Neither the name of the University nor the names of its contributors | ||
| 13 | .\" may be used to endorse or promote products derived from this software | ||
| 14 | .\" without specific prior written permission. | ||
| 15 | .\" | ||
| 16 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | ||
| 17 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
| 18 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||
| 19 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | ||
| 20 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | ||
| 21 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | ||
| 22 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
| 23 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||
| 24 | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | ||
| 25 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | ||
| 26 | .\" SUCH DAMAGE. | ||
| 27 | .\" | ||
| 28 | .\" $OpenBSD: getopt.3,v 1.28 2003/09/22 23:47:26 millert Exp $ | ||
| 29 | .\" | ||
| 30 | .Dd December 17, 2002 | ||
| 31 | .Dt GETOPT 3 | ||
| 32 | .Os | ||
| 33 | .Sh NAME | ||
| 34 | .Nm getopt | ||
| 35 | .Nd get option character from command line argument list | ||
| 36 | .Sh SYNOPSIS | ||
| 37 | .Fd #include <unistd.h> | ||
| 38 | .Vt extern char *optarg; | ||
| 39 | .Vt extern int optind; | ||
| 40 | .Vt extern int optopt; | ||
| 41 | .Vt extern int opterr; | ||
| 42 | .Vt extern int optreset; | ||
| 43 | .Ft int | ||
| 44 | .Fn getopt "int argc" "char * const *argv" "const char *optstring" | ||
| 45 | .Sh DESCRIPTION | ||
| 46 | The | ||
| 47 | .Fn getopt | ||
| 48 | function incrementally parses a command line argument list | ||
| 49 | .Fa argv | ||
| 50 | and returns the next | ||
| 51 | .Em known | ||
| 52 | option character. | ||
| 53 | An option character is | ||
| 54 | .Em known | ||
| 55 | if it has been specified in the string of accepted option characters, | ||
| 56 | .Fa optstring . | ||
| 57 | .Pp | ||
| 58 | The option string | ||
| 59 | .Fa optstring | ||
| 60 | may contain the following elements: individual characters, | ||
| 61 | characters followed by a colon, and characters followed by two colons. | ||
| 62 | A character followed by a single colon indicates that an argument | ||
| 63 | is to follow the option on the command line. | ||
| 64 | Two colons indicates that the argument is optional--this is an | ||
| 65 | extension not covered by | ||
| 66 | .Px . | ||
| 67 | For example, an option string | ||
| 68 | .Qq x | ||
| 69 | recognizes an option | ||
| 70 | .Fl x , | ||
| 71 | and an option string | ||
| 72 | .Qq Li x: | ||
| 73 | recognizes an option and argument | ||
| 74 | .Fl x Ar argument . | ||
| 75 | It does not matter to | ||
| 76 | .Fn getopt | ||
| 77 | if a following argument has leading whitespace. | ||
| 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 | .Pp | ||
| 91 | The variables | ||
| 92 | .Va opterr | ||
| 93 | and | ||
| 94 | .Va optind | ||
| 95 | are both initialized to 1. | ||
| 96 | The | ||
| 97 | .Va optind | ||
| 98 | variable may be set to another value before a set of calls to | ||
| 99 | .Fn getopt | ||
| 100 | in order to skip over more or less argv entries. | ||
| 101 | .Pp | ||
| 102 | In order to use | ||
| 103 | .Fn getopt | ||
| 104 | to evaluate multiple sets of arguments, or to evaluate a single set of | ||
| 105 | arguments multiple times, | ||
| 106 | the variable | ||
| 107 | .Va optreset | ||
| 108 | must be set to 1 before the second and each additional set of calls to | ||
| 109 | .Fn getopt , | ||
| 110 | and the variable | ||
| 111 | .Va optind | ||
| 112 | must be reinitialized. | ||
| 113 | .Pp | ||
| 114 | The | ||
| 115 | .Fn getopt | ||
| 116 | function returns \-1 when the argument list is exhausted. | ||
| 117 | The interpretation of options in the argument list may be cancelled | ||
| 118 | by the option | ||
| 119 | .Ql -- | ||
| 120 | (double dash) which causes | ||
| 121 | .Fn getopt | ||
| 122 | to signal the end of argument processing and return \-1. | ||
| 123 | When all options have been processed (i.e., up to the first non-option | ||
| 124 | argument), | ||
| 125 | .Fn getopt | ||
| 126 | returns \-1. | ||
| 127 | .Sh RETURN VALUES | ||
| 128 | The | ||
| 129 | .Fn getopt | ||
| 130 | function returns the next known option character in | ||
| 131 | .Fa optstring . | ||
| 132 | If | ||
| 133 | .Fn getopt | ||
| 134 | encounters a character not found in | ||
| 135 | .Fa optstring | ||
| 136 | or if it detects a missing option argument, | ||
| 137 | it returns | ||
| 138 | .Sq \&? | ||
| 139 | (question mark). | ||
| 140 | If | ||
| 141 | .Fa optstring | ||
| 142 | has a leading | ||
| 143 | .Sq \&: | ||
| 144 | then a missing option argument causes | ||
| 145 | .Sq \&: | ||
| 146 | to be returned instead of | ||
| 147 | .Sq \&? . | ||
| 148 | In either case, the variable | ||
| 149 | .Va optopt | ||
| 150 | is set to the character that caused the error. | ||
| 151 | The | ||
| 152 | .Fn getopt | ||
| 153 | function returns \-1 when the argument list is exhausted. | ||
| 154 | .Sh ENVIRONMENT | ||
| 155 | .Bl -tag -width POSIXLY_CORRECTXX | ||
| 156 | .It Ev POSIXLY_CORRECT | ||
| 157 | If set, a leading | ||
| 158 | .Sq - | ||
| 159 | in | ||
| 160 | .Ar optstring | ||
| 161 | is ignored. | ||
| 162 | .El | ||
| 163 | .Sh EXAMPLES | ||
| 164 | .Bd -literal -compact | ||
| 165 | extern char *optarg; | ||
| 166 | extern int optind; | ||
| 167 | int bflag, ch, fd; | ||
| 168 | |||
| 169 | bflag = 0; | ||
| 170 | while ((ch = getopt(argc, argv, "bf:")) != -1) { | ||
| 171 | switch (ch) { | ||
| 172 | case 'b': | ||
| 173 | bflag = 1; | ||
| 174 | break; | ||
| 175 | case 'f': | ||
| 176 | if ((fd = open(optarg, O_RDONLY, 0)) < 0) { | ||
| 177 | (void)fprintf(stderr, | ||
| 178 | "myname: %s: %s\en", optarg, strerror(errno)); | ||
| 179 | exit(1); | ||
| 180 | } | ||
| 181 | break; | ||
| 182 | case '?': | ||
| 183 | default: | ||
| 184 | usage(); | ||
| 185 | } | ||
| 186 | } | ||
| 187 | argc -= optind; | ||
| 188 | argv += optind; | ||
| 189 | .Ed | ||
| 190 | .Sh DIAGNOSTICS | ||
| 191 | If the | ||
| 192 | .Fn getopt | ||
| 193 | function encounters a character not found in the string | ||
| 194 | .Fa optstring | ||
| 195 | or detects | ||
| 196 | a missing option argument it writes an error message to | ||
| 197 | .Em stderr | ||
| 198 | and returns | ||
| 199 | .Ql \&? . | ||
| 200 | Setting | ||
| 201 | .Va opterr | ||
| 202 | to a zero will disable these error messages. | ||
| 203 | If | ||
| 204 | .Fa optstring | ||
| 205 | has a leading | ||
| 206 | .Ql \&: | ||
| 207 | then a missing option argument causes a | ||
| 208 | .Ql \&: | ||
| 209 | to be returned in addition to suppressing any error messages. | ||
| 210 | .Pp | ||
| 211 | Option arguments are allowed to begin with | ||
| 212 | .Ql - ; | ||
| 213 | this is reasonable but reduces the amount of error checking possible. | ||
| 214 | .Sh SEE ALSO | ||
| 215 | .Xr getopt 1 , | ||
| 216 | .Xr getopt_long 3 , | ||
| 217 | .Xr getsubopt 3 | ||
| 218 | .Sh STANDARDS | ||
| 219 | The | ||
| 220 | .Fn getopt | ||
| 221 | function implements a superset of the functionality specified by | ||
| 222 | .St -p1003.1 . | ||
| 223 | .Pp | ||
| 224 | The following extensions are supported: | ||
| 225 | .Bl -tag -width "xxx" | ||
| 226 | .It Li o | ||
| 227 | The | ||
| 228 | .Va optreset | ||
| 229 | variable was added to make it possible to call the | ||
| 230 | .Fn getopt | ||
| 231 | function multiple times. | ||
| 232 | .It Li o | ||
| 233 | If the first character of | ||
| 234 | .Fa optstring | ||
| 235 | is a plus sign | ||
| 236 | .Pq Ql + , | ||
| 237 | it will be ignored. | ||
| 238 | This is for compatibility with | ||
| 239 | .Tn GNU | ||
| 240 | .Fn getopt . | ||
| 241 | .It Li o | ||
| 242 | If the first character of | ||
| 243 | .Fa optstring | ||
| 244 | is a dash | ||
| 245 | .Pq Ql - , | ||
| 246 | non-options will be returned as arguments to the option character | ||
| 247 | .Ql \e1 . | ||
| 248 | This is for compatibility with | ||
| 249 | .Tn GNU | ||
| 250 | .Fn getopt . | ||
| 251 | .It Li o | ||
| 252 | A single dash | ||
| 253 | .Pq Ql - | ||
| 254 | may be specified as a character in | ||
| 255 | .Fa optstring , | ||
| 256 | however it should | ||
| 257 | .Em never | ||
| 258 | have an argument associated with it. | ||
| 259 | This allows | ||
| 260 | .Fn getopt | ||
| 261 | to be used with programs that expect | ||
| 262 | .Ql - | ||
| 263 | as an option flag. | ||
| 264 | This practice is wrong, and should not be used in any current development. | ||
| 265 | It is provided for backward compatibility | ||
| 266 | .Em only . | ||
| 267 | Care should be taken not to use | ||
| 268 | .Ql - | ||
| 269 | as the first character in | ||
| 270 | .Fa optstring | ||
| 271 | to avoid a semantic conflict with | ||
| 272 | .Tn GNU | ||
| 273 | .Fn getopt | ||
| 274 | semantics (see above). | ||
| 275 | By default, a single dash causes | ||
| 276 | .Fn getopt | ||
| 277 | to return \-1. | ||
| 278 | .El | ||
| 279 | .Pp | ||
| 280 | Unlike | ||
| 281 | .Tn GNU | ||
| 282 | .Fn getopt , | ||
| 283 | .Ox | ||
| 284 | does not permute the argument vector to allow non-options to be | ||
| 285 | interspersed with options on the command line. | ||
| 286 | Programs requiring this behavior should use | ||
| 287 | .Xr getopt_long 3 | ||
| 288 | instead. | ||
| 289 | Because of this (and unlike | ||
| 290 | .Tn GNU ) , | ||
| 291 | the | ||
| 292 | .Ox | ||
| 293 | .Fn getopt | ||
| 294 | supports optional arguments separated by whitespace. | ||
| 295 | .Sh HISTORY | ||
| 296 | The | ||
| 297 | .Fn getopt | ||
| 298 | function appeared in | ||
| 299 | .Bx 4.3 . | ||
| 300 | .Sh BUGS | ||
| 301 | The | ||
| 302 | .Fn getopt | ||
| 303 | function was once specified to return | ||
| 304 | .Dv EOF | ||
| 305 | instead of \-1. | ||
| 306 | This was changed by | ||
| 307 | .St -p1003.2-92 | ||
| 308 | to decouple | ||
| 309 | .Fn getopt | ||
| 310 | from | ||
| 311 | .Aq Pa stdio.h . | ||
| 312 | .Pp | ||
| 313 | It is possible to handle digits as option letters. | ||
| 314 | This allows | ||
| 315 | .Fn getopt | ||
| 316 | to be used with programs that expect a number | ||
| 317 | .Pq Dq Li \-3 | ||
| 318 | as an option. | ||
| 319 | This practice is wrong, and should not be used in any current development. | ||
| 320 | It is provided for backward compatibility | ||
| 321 | .Em only . | ||
| 322 | The following code fragment works in most cases. | ||
| 323 | .Bd -literal -offset indent | ||
| 324 | int ch; | ||
| 325 | long length; | ||
| 326 | char *p; | ||
| 327 | |||
| 328 | while ((ch = getopt(argc, argv, "0123456789")) != -1) { | ||
| 329 | switch (ch) { | ||
| 330 | case '0': case '1': case '2': case '3': case '4': | ||
| 331 | case '5': case '6': case '7': case '8': case '9': | ||
| 332 | p = argv[optind - 1]; | ||
| 333 | if (p[0] == '-' && p[1] == ch && !p[2]) | ||
| 334 | length = ch - '0'; | ||
| 335 | else | ||
| 336 | length = strtol(argv[optind] + 1, NULL, 10); | ||
| 337 | break; | ||
| 338 | } | ||
| 339 | } | ||
| 340 | .Ed | ||
