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 Li 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.Li 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 EXAMPLES 217.Bd -literal -compact 218int bflag, ch, fd; 219int daggerset; 220 221/* options descriptor */ 222static struct option longopts[] = { 223 { "buffy", no_argument, NULL, 'b' }, 224 { "fluoride", required_argument, NULL, 'f' }, 225 { "daggerset", no_argument, \*[Am]daggerset, 1 }, 226 { NULL, 0, NULL, 0 } 227}; 228 229bflag = 0; 230while ((ch = getopt_long(argc, argv, "bf:", longopts, NULL)) != -1) 231 switch (ch) { 232 case 'b': 233 bflag = 1; 234 break; 235 case 'f': 236 if ((fd = open(optarg, O_RDONLY, 0)) == -1) 237 err(1, "unable to open %s", optarg); 238 break; 239 case 0: 240 if (daggerset) { 241 fprintf(stderr,"Buffy will use her dagger to " 242 "apply fluoride to dracula's teeth\en"); 243 } 244 break; 245 default: 246 usage(); 247} 248argc -= optind; 249argv += optind; 250.Ed 251.Sh IMPLEMENTATION DIFFERENCES 252This section describes differences to the 253.Tn GNU 254implementation 255found in glibc-2.1.3: 256.Bl -bullet 257.\" .It 258.\" Handling of 259.\" .Ql - 260.\" as first char of option string in presence of 261.\" environment variable 262.\" .Ev POSIXLY_CORRECT : 263.\" .Bl -tag -width ".Bx" 264.\" .It Tn GNU 265.\" ignores 266.\" .Ev POSIXLY_CORRECT 267.\" and returns non-options as 268.\" arguments to option '\e1'. 269.\" .It Bx 270.\" honors 271.\" .Ev POSIXLY_CORRECT 272.\" and stops at the first non-option. 273.\" .El 274.\" .It 275.\" Handling of 276.\" .Ql - 277.\" within the option string (not the first character): 278.\" .Bl -tag -width ".Bx" 279.\" .It Tn GNU 280.\" treats a 281.\" .Ql - 282.\" on the command line as a non-argument. 283.\" .It Bx 284.\" a 285.\" .Ql - 286.\" within the option string matches a 287.\" .Ql - 288.\" (single dash) on the command line. 289.\" This functionality is provided for backward compatibility with 290.\" programs, such as 291.\" .Xr su 1 , 292.\" that use 293.\" .Ql - 294.\" as an option flag. 295.\" This practice is wrong, and should not be used in any current development. 296.\" .El 297.\" .It 298.\" Handling of 299.\" .Ql :: 300.\" in options string in presence of 301.\" .Ev POSIXLY_CORRECT : 302.\" .Bl -tag -width ".Bx" 303.\" .It Both 304.\" .Tn GNU 305.\" and 306.\" .Bx 307.\" ignore 308.\" .Ev POSIXLY_CORRECT 309.\" here and take 310.\" .Ql :: 311.\" to 312.\" mean the preceding option takes an optional argument. 313.\" .El 314.\" .It 315.\" Return value in case of missing argument if first character 316.\" (after 317.\" .Ql + 318.\" or 319.\" .Ql - ) 320.\" in option string is not 321.\" .Ql \&: : 322.\" .Bl -tag -width ".Bx" 323.\" .It Tn GNU 324.\" returns 325.\" .Ql \&? 326.\" .It Bx 327.\" returns 328.\" .Ql \&: 329.\" (since 330.\" .Bx Ns 's 331.\" .Fn getopt 332.\" does). 333.\" .El 334.\" .It 335.\" Handling of 336.\" .Ql --a 337.\" in getopt: 338.\" .Bl -tag -width ".Bx" 339.\" .It Tn GNU 340.\" parses this as option 341.\" .Ql - , 342.\" option 343.\" .Ql a . 344.\" .It Bx 345.\" parses this as 346.\" .Ql -- , 347.\" and returns \-1 (ignoring the 348.\" .Ql a ) . 349.\" (Because the original 350.\" .Fn getopt 351.\" does.) 352.\" .El 353.It 354Setting of 355.Va optopt 356for long options with 357.Va flag 358!= 359.Dv NULL : 360.Bl -tag -width ".Bx" 361.It Tn GNU 362sets 363.Va optopt 364to 365.Va val . 366.It Bx 367sets 368.Va optopt 369to 0 (since 370.Va val 371would never be returned). 372.El 373.\" .It 374.\" Handling of 375.\" .Ql -W 376.\" with 377.\" .Ql W; 378.\" in option string in 379.\" .Fn getopt 380.\" (not 381.\" .Fn getopt_long ) : 382.\" .Bl -tag -width ".Bx" 383.\" .It Tn GNU 384.\" causes a segfault. 385.\" .It Bx 386.\" no special handling is done; 387.\" .Ql W; 388.\" is interpreted as two separate options, neither of which take an argument. 389.\" .El 390.It 391Setting of 392.Va optarg 393for long options without an argument that are 394invoked via 395.Ql -W 396.Ql ( W; 397in option string): 398.Bl -tag -width ".Bx" 399.It Tn GNU 400sets 401.Va optarg 402to the option name (the argument of 403.Ql -W ) . 404.It Bx 405sets 406.Va optarg 407to 408.Dv NULL 409(the argument of the long option). 410.El 411.It 412Handling of 413.Ql -W 414with an argument that is not (a prefix to) a known 415long option 416.Ql ( W; 417in option string): 418.Bl -tag -width ".Bx" 419.It Tn GNU 420returns 421.Ql -W 422with 423.Va optarg 424set to the unknown option. 425.It Bx 426treats this as an error (unknown option) and returns 427.Ql \&? 428with 429.Va optopt 430set to 0 and 431.Va optarg 432set to 433.Dv NULL 434(as 435.Tn GNU Ns 's 436man page documents). 437.El 438.\" .It 439.\" The error messages are different. 440.It 441.Bx 442does not permute the argument vector at the same points in 443the calling sequence as 444.Tn GNU 445does. 446The aspects normally used by 447the caller (ordering after \-1 is returned, value of 448.Va optind 449relative 450to current positions) are the same, though. 451(We do fewer variable swaps.) 452.El 453.Sh ENVIRONMENT 454.Bl -tag -width POSIXLY_CORRECT 455.It Ev POSIXLY_CORRECT 456If set, option processing stops when the first non-option is found and 457a leading 458.Ql - 459or 460.Ql + 461in the 462.Ar optstring 463is ignored. 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 473.Tn GNU 474libiberty. 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.Ar argv 498argument is not really 499.Dv 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