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 December 25, 2011 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 expected 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 } 260} 261argc -= optind; 262argv += optind; 263.Ed 264.Sh IMPLEMENTATION DIFFERENCES 265This section describes differences to the 266.Tn GNU 267implementation 268found in glibc-2.1.3: 269.Bl -bullet 270.\" .It 271.\" Handling of 272.\" .Ql - 273.\" as first char of option string in presence of 274.\" environment variable 275.\" .Ev POSIXLY_CORRECT : 276.\" .Bl -tag -width ".Bx" 277.\" .It Tn GNU 278.\" ignores 279.\" .Ev POSIXLY_CORRECT 280.\" and returns non-options as 281.\" arguments to option '\e1'. 282.\" .It Bx 283.\" honors 284.\" .Ev POSIXLY_CORRECT 285.\" and stops at the first non-option. 286.\" .El 287.\" .It 288.\" Handling of 289.\" .Ql - 290.\" within the option string (not the first character): 291.\" .Bl -tag -width ".Bx" 292.\" .It Tn GNU 293.\" treats a 294.\" .Ql - 295.\" on the command line as a non-argument. 296.\" .It Bx 297.\" a 298.\" .Ql - 299.\" within the option string matches a 300.\" .Ql - 301.\" (single dash) on the command line. 302.\" This functionality is provided for backward compatibility with 303.\" programs, such as 304.\" .Xr su 1 , 305.\" that use 306.\" .Ql - 307.\" as an option flag. 308.\" This practice is wrong, and should not be used in any current development. 309.\" .El 310.\" .It 311.\" Handling of 312.\" .Ql :: 313.\" in options string in presence of 314.\" .Ev POSIXLY_CORRECT : 315.\" .Bl -tag -width ".Bx" 316.\" .It Both 317.\" .Tn GNU 318.\" and 319.\" .Bx 320.\" ignore 321.\" .Ev POSIXLY_CORRECT 322.\" here and take 323.\" .Ql :: 324.\" to 325.\" mean the preceding option takes an optional argument. 326.\" .El 327.\" .It 328.\" Return value in case of missing argument if first character 329.\" (after 330.\" .Ql + 331.\" or 332.\" .Ql - ) 333.\" in option string is not 334.\" .Ql \&: : 335.\" .Bl -tag -width ".Bx" 336.\" .It Tn GNU 337.\" returns 338.\" .Ql \&? 339.\" .It Bx 340.\" returns 341.\" .Ql \&: 342.\" (since 343.\" .Bx Ns 's 344.\" .Fn getopt 345.\" does). 346.\" .El 347.\" .It 348.\" Handling of 349.\" .Ql --a 350.\" in getopt: 351.\" .Bl -tag -width ".Bx" 352.\" .It Tn GNU 353.\" parses this as option 354.\" .Ql - , 355.\" option 356.\" .Ql a . 357.\" .It Bx 358.\" parses this as 359.\" .Ql -- , 360.\" and returns \-1 (ignoring the 361.\" .Ql a ) . 362.\" (Because the original 363.\" .Fn getopt 364.\" does.) 365.\" .El 366.It 367Setting of 368.Va optopt 369for long options with 370.Va flag 371!= 372.Dv NULL : 373.Bl -tag -width ".Bx" 374.It Tn GNU 375sets 376.Va optopt 377to 378.Va val . 379.It Bx 380sets 381.Va optopt 382to 0 (since 383.Va val 384would never be returned). 385.El 386.\" .It 387.\" Handling of 388.\" .Ql -W 389.\" with 390.\" .Ql W; 391.\" in option string in 392.\" .Fn getopt 393.\" (not 394.\" .Fn getopt_long ) : 395.\" .Bl -tag -width ".Bx" 396.\" .It Tn GNU 397.\" causes a segfault. 398.\" .It Bx 399.\" no special handling is done; 400.\" .Ql W; 401.\" is interpreted as two separate options, neither of which take an argument. 402.\" .El 403.It 404Setting of 405.Va optarg 406for long options without an argument that are 407invoked via 408.Ql -W 409.Ql ( W; 410in option string): 411.Bl -tag -width ".Bx" 412.It Tn GNU 413sets 414.Va optarg 415to the option name (the argument of 416.Ql -W ) . 417.It Bx 418sets 419.Va optarg 420to 421.Dv NULL 422(the argument of the long option). 423.El 424.It 425Handling of 426.Ql -W 427with an argument that is not (a prefix to) a known 428long option 429.Ql ( W; 430in option string): 431.Bl -tag -width ".Bx" 432.It Tn GNU 433returns 434.Ql -W 435with 436.Va optarg 437set to the unknown option. 438.It Bx 439treats this as an error (unknown option) and returns 440.Ql \&? 441with 442.Va optopt 443set to 0 and 444.Va optarg 445set to 446.Dv NULL 447(as 448.Tn GNU Ns 's 449man page documents). 450.El 451.\" .It 452.\" The error messages are different. 453.It 454.Bx 455does not permute the argument vector at the same points in 456the calling sequence as 457.Tn GNU 458does. 459The aspects normally used by 460the caller (ordering after \-1 is returned, value of 461.Va optind 462relative 463to current positions) are the same, though. 464(We do fewer variable swaps.) 465.El 466.Sh SEE ALSO 467.Xr getopt 3 468.Sh HISTORY 469The 470.Fn getopt_long 471and 472.Fn getopt_long_only 473functions first appeared in the 474.Tn GNU 475libiberty library. 476The first 477.Bx 478implementation of 479.Fn getopt_long 480appeared in 481.Nx 1.5 , 482the first 483.Bx 484implementation of 485.Fn getopt_long_only 486in 487.Ox 3.3 . 488.Fx 489first included 490.Fn getopt_long 491in 492.Fx 5.0 , 493.Fn getopt_long_only 494in 495.Fx 5.2 . 496.Sh BUGS 497The 498.Fa argv 499argument is not really 500.Vt const 501as its elements may be permuted (unless 502.Ev POSIXLY_CORRECT 503is set). 504.Pp 505The implementation can completely replace 506.Xr getopt 3 , 507but right now we are using separate code. 508