1.\" $NetBSD: getopt_long.3,v 1.8 2002/06/03 12:01:43 wiz Exp $ 2.\" $FreeBSD$ 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. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)getopt.3 8.5 (Berkeley) 4/27/95 36.\" 37.Dd April 1, 2000 38.Dt GETOPT_LONG 3 39.Os 40.Sh NAME 41.Nm getopt_long 42.Nd get long options from command line argument list 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.Fd #include \*[Lt]getopt.h\*[Gt] 47.Ft int 48.Fn getopt_long "int argc" "char * const *argv" "const char *optstring" "struct option *long options" "int *index" 49.Sh DESCRIPTION 50The 51.Fn getopt_long 52function is similar to 53.Xr getopt 3 54but it accepts options in two forms: words and characters. The 55.Fn getopt_long 56function provides a superset of of the functionality of 57.Xr getopt 3 . 58.Fn getopt_long 59can be used in two ways. In the first way, every long option understood 60by the program has a corresponding short option, and the option 61structure is only used to translate from long options to short 62options. When used in this fashion, 63.Fn getopt_long 64behaves identically to 65.Xr getopt 3 . 66This is a good way to add long option processing to an existing program 67with the minimum of rewriting. 68.Pp 69In the second mechanism, a long option sets a flag in the 70.Fa option 71structure passed, or will store a pointer to the command line argument 72in the 73.Fa option 74structure passed to it for options that take arguments. Additionally, 75the long option's argument may be specified as a single argument with 76an equal sign, e.g. 77.Bd -literal 78myprogram --myoption=somevalue 79.Ed 80.Pp 81When a long option is processed the call to 82.Fn getopt_long 83will return 0. For this reason, long option processing without 84shortcuts is not backwards compatible with 85.Xr getopt 3 . 86.Pp 87It is possible to combine these methods, providing for long options 88processing with short option equivalents for some options. Less 89frequently used options would be processed as long options only. 90.Pp 91The 92.Fn getopt_long 93call requires a structure to be initialized describing the long 94options. The structure is: 95.Bd -literal 96struct option { 97 char *name; 98 int has_arg; 99 int *flag; 100 int val; 101}; 102.Ed 103.Pp 104The 105.Fa name 106field should contain the option name without the leading double dash. 107.Pp 108The 109.Fa has_arg 110field should be one of: 111.Bl -tag -width "optional_argument" 112.It Li no_argument 113no argument to the option is expect. 114.It Li required_argument 115an argument to the option is required. 116.It Li optional_argument 117an argument to the option may be presented. 118.El 119.Pp 120If 121.Fa flag 122is non-NULL, then the integer pointed to by it will be set to the 123value in the 124.Fa val 125field. If the 126.Fa flag 127field is NULL, then the 128.Fa val 129field will be returned. Setting 130.Fa flag 131to NULL and setting 132.Fa val 133to the corresponding short option will make this function act just 134like 135.Xr getopt 3 . 136.Sh EXAMPLES 137.Bd -literal -compact 138extern char *optarg; 139extern int optind; 140int bflag, ch, fd; 141int daggerset; 142 143/* options descriptor */ 144static struct option longopts[] = { 145 { "buffy", no_argument, 0, 'b' }, 146 { "floride", required_argument, 0, 'f' }, 147 { "daggerset", no_argument, \*[Am]daggerset, 1 }, 148 { 0, 0, 0, 0 } 149}; 150 151bflag = 0; 152while ((ch = getopt_long(argc, argv, "bf:", longopts, NULL)) != -1) 153 switch(ch) { 154 case 'b': 155 bflag = 1; 156 break; 157 case 'f': 158 if ((fd = open(optarg, O_RDONLY, 0)) \*[Lt] 0) { 159 (void)fprintf(stderr, 160 "myname: %s: %s\en", optarg, strerror(errno)); 161 exit(1); 162 } 163 break; 164 case 0: 165 if(daggerset) { 166 fprintf(stderr,"Buffy will use her dagger to " 167 "apply floride to dracula's teeth\en"); 168 } 169 break; 170 case '?': 171 default: 172 usage(); 173} 174argc -= optind; 175argv += optind; 176.Ed 177.Sh IMPLEMENTATION DIFFERENCES 178This section describes differences to the GNU implementation 179found in glibc-2.1.3: 180.Bl -tag -width "xxx" 181.It Li o 182handling of - as first char of option string in presence of 183environment variable POSIXLY_CORRECT: 184.Bl -tag -width "NetBSD" 185.It Li GNU 186ignores POSIXLY_CORRECT and returns non-options as 187arguments to option '\e1'. 188.It Li NetBSD 189honors POSIXLY_CORRECT and stops at the first non-option. 190.El 191.It Li o 192handling of :: in options string in presence of POSIXLY_CORRECT: 193.Bl -tag -width "NetBSD" 194.It Li Both 195GNU and NetBSD ignore POSIXLY_CORRECT here and take :: to 196mean the preceding option takes an optional argument. 197.El 198.It Li o 199return value in case of missing argument if first character 200(after + or -) in option string is not ':': 201.Bl -tag -width "NetBSD" 202.It Li GNU 203returns '?' 204.It NetBSD 205returns ':' (since NetBSD's getopt does). 206.El 207.It Li o 208handling of --a in getopt: 209.Bl -tag -width "NetBSD" 210.It Li GNU 211parses this as option '-', option 'a'. 212.It Li NetBSD 213parses this as '--', and returns -1 (ignoring the a). (Because 214the original getopt does.) 215.El 216.It Li o 217setting of optopt for long options with flag != NULL: 218.Bl -tag -width "NetBSD" 219.It Li GNU 220sets optopt to val. 221.It Li NetBSD 222sets optopt to 0 (since val would never be returned). 223.El 224.It Li o 225handling of -W with W; in option string in getopt (not getopt_long): 226.Bl -tag -width "NetBSD" 227.It Li GNU 228causes a segfault. 229.It Li NetBSD 230returns -1, with optind pointing past the argument of -W 231(as if `-W arg' were `--arg', and thus '--' had been found). 232.\" How should we treat W; in the option string when called via 233.\" getopt? Ignore the ';' or treat it as a ':'? Issue a warning? 234.El 235.It Li o 236setting of optarg for long options without an argument that are 237invoked via -W (W; in option string): 238.Bl -tag -width "NetBSD" 239.It Li GNU 240sets optarg to the option name (the argument of -W). 241.It Li NetBSD 242sets optarg to NULL (the argument of the long option). 243.El 244.It Li o 245handling of -W with an argument that is not (a prefix to) a known 246long option (W; in option string): 247.Bl -tag -width "NetBSD" 248.It Li GNU 249returns -W with optarg set to the unknown option. 250.It Li NetBSD 251treats this as an error (unknown option) and returns '?' with 252optopt set to 0 and optarg set to NULL (as GNU's man page 253documents). 254.El 255.It Li o 256The error messages are different. 257.It Li o 258NetBSD does not permute the argument vector at the same points in 259the calling sequence as GNU does. The aspects normally used by 260the caller (ordering after -1 is returned, value of optind relative 261to current positions) are the same, though. (We do fewer variable 262swaps.) 263.El 264.Sh SEE ALSO 265.Xr getopt 3 266.Sh HISTORY 267The 268.Fn getopt_long 269function first appeared in GNU libiberty. The first 270.Nx 271implementation appeared in 1.5. 272.Sh BUGS 273The implementation, can completelely replace 274.Xr getopt 3 , 275but right now we are using separate code. 276