1.\" $OpenBSD: getopt_long.3,v 1.10 2004/01/06 23:44:28 fgsch Exp $ 2.\" $NetBSD: getopt_long.3,v 1.14 2003/08/07 16:43:40 agc Exp $ 3.\" 4.\" Copyright (c) 1988, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)getopt.3 8.5 (Berkeley) 4/27/95 32.\" $FreeBSD$ 33.\" 34.Dd April 1, 2000 35.Dt GETOPT_LONG 3 36.Os 37.Sh NAME 38.Nm getopt_long , 39.Nm getopt_long_only 40.Nd get long options from command line argument list 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In getopt.h 45.Vt extern char *optarg ; 46.Vt extern int optind ; 47.Vt extern int optopt ; 48.Vt extern int opterr ; 49.Vt extern int optreset ; 50.Ft int 51.Fo getopt_long 52.Fa "int argc" "char * const *argv" "const char *optstring" 53.Fa "const struct option *longopts" "int *longindex" 54.Fc 55.Ft int 56.Fo getopt_long_only 57.Fa "int argc" "char * const *argv" "const char *optstring" 58.Fa "const struct option *longopts" "int *longindex" 59.Fc 60.Sh DESCRIPTION 61The 62.Fn getopt_long 63function is similar to 64.Xr getopt 3 65but it accepts options in two forms: words and characters. 66The 67.Fn getopt_long 68function provides a superset of the functionality of 69.Xr getopt 3 . 70The 71.Fn getopt_long 72function 73can be used in two ways. 74In the first way, every long option understood 75by the program has a corresponding short option, and the option 76structure is only used to translate from long options to short 77options. 78When used in this fashion, 79.Fn getopt_long 80behaves identically to 81.Xr getopt 3 . 82This is a good way to add long option processing to an existing program 83with the minimum of rewriting. 84.Pp 85In the second mechanism, a long option sets a flag in the 86.Vt option 87structure passed, or will store a pointer to the command line argument 88in the 89.Vt option 90structure passed to it for options that take arguments. 91Additionally, 92the long option's argument may be specified as a single argument with 93an equal sign, e.g., 94.Pp 95.Dl "myprogram --myoption=somevalue" 96.Pp 97When a long option is processed, the call to 98.Fn getopt_long 99will return 0. 100For this reason, long option processing without 101shortcuts is not backwards compatible with 102.Xr getopt 3 . 103.Pp 104It is possible to combine these methods, providing for long options 105processing with short option equivalents for some options. 106Less 107frequently used options would be processed as long options only. 108.Pp 109The 110.Fn getopt_long 111call requires a structure to be initialized describing the long 112options. 113The structure is: 114.Bd -literal -offset indent 115struct option { 116 char *name; 117 int has_arg; 118 int *flag; 119 int val; 120}; 121.Ed 122.Pp 123The 124.Va name 125field should contain the option name without the leading double dash. 126.Pp 127The 128.Va has_arg 129field should be one of: 130.Pp 131.Bl -tag -width ".Dv optional_argument" -offset indent -compact 132.It Dv no_argument 133no argument to the option is expect 134.It Dv required_argument 135an argument to the option is required 136.It Dv optional_argument 137an argument to the option may be presented. 138.El 139.Pp 140If 141.Va flag 142is not 143.Dv NULL , 144then the integer pointed to by it will be set to the 145value in the 146.Va val 147field. 148If the 149.Va flag 150field is 151.Dv NULL , 152then the 153.Va val 154field will be returned. 155Setting 156.Va flag 157to 158.Dv NULL 159and setting 160.Va val 161to the corresponding short option will make this function act just 162like 163.Xr getopt 3 . 164.Pp 165If the 166.Fa longindex 167field is not 168.Dv NULL , 169then the integer pointed to by it will be set to the index of the long 170option relative to 171.Fa longopts . 172.Pp 173The last element of the 174.Fa longopts 175array has to be filled with zeroes. 176.Pp 177The 178.Fn getopt_long_only 179function behaves identically to 180.Fn getopt_long 181with the exception that long options may start with 182.Ql - 183in addition to 184.Ql -- . 185If an option starting with 186.Ql - 187does not match a long option but does match a single-character option, 188the single-character option is returned. 189.Sh RETURN VALUES 190If the 191.Fa flag 192field in 193.Vt "struct option" 194is 195.Dv NULL , 196.Fn getopt_long 197and 198.Fn getopt_long_only 199return the value specified in the 200.Fa val 201field, which is usually just the corresponding short option. 202If 203.Fa flag 204is not 205.Dv NULL , 206these functions return 0 and store 207.Fa val 208in the location pointed to by 209.Fa flag . 210These functions return 211.Ql \&: 212if there was a missing option argument, 213.Ql \&? 214if the user specified an unknown or ambiguous option, and 215\-1 when the argument list has been exhausted. 216.Sh ENVIRONMENT 217.Bl -tag -width ".Ev POSIXLY_CORRECT" 218.It Ev POSIXLY_CORRECT 219If set, option processing stops when the first non-option is found and 220a leading 221.Ql - 222or 223.Ql + 224in the 225.Fa optstring 226is ignored. 227.El 228.Sh EXAMPLES 229.Bd -literal -compact 230int bflag, ch, fd; 231int daggerset; 232 233/* options descriptor */ 234static struct option longopts[] = { 235 { "buffy", no_argument, NULL, 'b' }, 236 { "fluoride", required_argument, NULL, 'f' }, 237 { "daggerset", no_argument, \*[Am]daggerset, 1 }, 238 { NULL, 0, NULL, 0 } 239}; 240 241bflag = 0; 242while ((ch = getopt_long(argc, argv, "bf:", longopts, NULL)) != -1) 243 switch (ch) { 244 case 'b': 245 bflag = 1; 246 break; 247 case 'f': 248 if ((fd = open(optarg, O_RDONLY, 0)) == -1) 249 err(1, "unable to open %s", optarg); 250 break; 251 case 0: 252 if (daggerset) { 253 fprintf(stderr,"Buffy will use her dagger to " 254 "apply fluoride to dracula's teeth\en"); 255 } 256 break; 257 default: 258 usage(); 259} 260argc -= optind; 261argv += optind; 262.Ed 263.Sh IMPLEMENTATION DIFFERENCES 264This section describes differences to the 265.Tn GNU 266implementation 267found in glibc-2.1.3: 268.Bl -bullet 269.\" .It 270.\" Handling of 271.\" .Ql - 272.\" as first char of option string in presence of 273.\" environment variable 274.\" .Ev POSIXLY_CORRECT : 275.\" .Bl -tag -width ".Bx" 276.\" .It Tn GNU 277.\" ignores 278.\" .Ev POSIXLY_CORRECT 279.\" and returns non-options as 280.\" arguments to option '\e1'. 281.\" .It Bx 282.\" honors 283.\" .Ev POSIXLY_CORRECT 284.\" and stops at the first non-option. 285.\" .El 286.\" .It 287.\" Handling of 288.\" .Ql - 289.\" within the option string (not the first character): 290.\" .Bl -tag -width ".Bx" 291.\" .It Tn GNU 292.\" treats a 293.\" .Ql - 294.\" on the command line as a non-argument. 295.\" .It Bx 296.\" a 297.\" .Ql - 298.\" within the option string matches a 299.\" .Ql - 300.\" (single dash) on the command line. 301.\" This functionality is provided for backward compatibility with 302.\" programs, such as 303.\" .Xr su 1 , 304.\" that use 305.\" .Ql - 306.\" as an option flag. 307.\" This practice is wrong, and should not be used in any current development. 308.\" .El 309.\" .It 310.\" Handling of 311.\" .Ql :: 312.\" in options string in presence of 313.\" .Ev POSIXLY_CORRECT : 314.\" .Bl -tag -width ".Bx" 315.\" .It Both 316.\" .Tn GNU 317.\" and 318.\" .Bx 319.\" ignore 320.\" .Ev POSIXLY_CORRECT 321.\" here and take 322.\" .Ql :: 323.\" to 324.\" mean the preceding option takes an optional argument. 325.\" .El 326.\" .It 327.\" Return value in case of missing argument if first character 328.\" (after 329.\" .Ql + 330.\" or 331.\" .Ql - ) 332.\" in option string is not 333.\" .Ql \&: : 334.\" .Bl -tag -width ".Bx" 335.\" .It Tn GNU 336.\" returns 337.\" .Ql \&? 338.\" .It Bx 339.\" returns 340.\" .Ql \&: 341.\" (since 342.\" .Bx Ns 's 343.\" .Fn getopt 344.\" does). 345.\" .El 346.\" .It 347.\" Handling of 348.\" .Ql --a 349.\" in getopt: 350.\" .Bl -tag -width ".Bx" 351.\" .It Tn GNU 352.\" parses this as option 353.\" .Ql - , 354.\" option 355.\" .Ql a . 356.\" .It Bx 357.\" parses this as 358.\" .Ql -- , 359.\" and returns \-1 (ignoring the 360.\" .Ql a ) . 361.\" (Because the original 362.\" .Fn getopt 363.\" does.) 364.\" .El 365.It 366Setting of 367.Va optopt 368for long options with 369.Va flag 370!= 371.Dv NULL : 372.Bl -tag -width ".Bx" 373.It Tn GNU 374sets 375.Va optopt 376to 377.Va val . 378.It Bx 379sets 380.Va optopt 381to 0 (since 382.Va val 383would never be returned). 384.El 385.\" .It 386.\" Handling of 387.\" .Ql -W 388.\" with 389.\" .Ql W; 390.\" in option string in 391.\" .Fn getopt 392.\" (not 393.\" .Fn getopt_long ) : 394.\" .Bl -tag -width ".Bx" 395.\" .It Tn GNU 396.\" causes a segfault. 397.\" .It Bx 398.\" no special handling is done; 399.\" .Ql W; 400.\" is interpreted as two separate options, neither of which take an argument. 401.\" .El 402.It 403Setting of 404.Va optarg 405for long options without an argument that are 406invoked via 407.Ql -W 408.Ql ( W; 409in option string): 410.Bl -tag -width ".Bx" 411.It Tn GNU 412sets 413.Va optarg 414to the option name (the argument of 415.Ql -W ) . 416.It Bx 417sets 418.Va optarg 419to 420.Dv NULL 421(the argument of the long option). 422.El 423.It 424Handling of 425.Ql -W 426with an argument that is not (a prefix to) a known 427long option 428.Ql ( W; 429in option string): 430.Bl -tag -width ".Bx" 431.It Tn GNU 432returns 433.Ql -W 434with 435.Va optarg 436set to the unknown option. 437.It Bx 438treats this as an error (unknown option) and returns 439.Ql \&? 440with 441.Va optopt 442set to 0 and 443.Va optarg 444set to 445.Dv NULL 446(as 447.Tn GNU Ns 's 448man page documents). 449.El 450.\" .It 451.\" The error messages are different. 452.It 453.Bx 454does not permute the argument vector at the same points in 455the calling sequence as 456.Tn GNU 457does. 458The aspects normally used by 459the caller (ordering after \-1 is returned, value of 460.Va optind 461relative 462to current positions) are the same, though. 463(We do fewer variable swaps.) 464.El 465.Sh SEE ALSO 466.Xr getopt 3 467.Sh HISTORY 468The 469.Fn getopt_long 470and 471.Fn getopt_long_only 472functions first appeared in the 473.Tn GNU 474libiberty library. 475The first 476.Bx 477implementation of 478.Fn getopt_long 479appeared in 480.Nx 1.5 , 481the first 482.Bx 483implementation of 484.Fn getopt_long_only 485in 486.Ox 3.3 . 487.Fx 488first included 489.Fn getopt_long 490in 491.Fx 5.0 , 492.Fn getopt_long_only 493in 494.Fx 5.2 . 495.Sh BUGS 496The 497.Fa argv 498argument is not really 499.Vt const 500as its elements may be permuted (unless 501.Ev POSIXLY_CORRECT 502is set). 503.Pp 504The implementation can completely replace 505.Xr getopt 3 , 506but right now we are using separate code. 507