1.\" $NetBSD: getopt_long.3,v 1.7 2002/02/07 09:24:06 ross Exp $ 2.\" 3.\" Copyright (c) 1988, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)getopt.3 8.5 (Berkeley) 4/27/95 35.\" 36.Dd April 1, 2000 37.Dt GETOPT_LONG 3 38.Os 39.Sh NAME 40.Nm getopt_long 41.Nd get long options from command line argument list 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]getopt.h\*[Gt] 46.Ft int 47.Fn getopt_long "int argc" "char * const *argv" "const char *optstring" "struct options *long options" "int *index" 48.Sh DESCRIPTION 49The 50.Fn getopt_long 51function is similar to 52.Xr getopt 3 53but it accepts options in two forms: words and characters. The 54.Fn getopt_long 55function provides a superset of of the functionality of 56.Xr getopt 3 . 57.Fn getopt_long 58can be used in two ways. In the first way, every long option understood 59by the program has a corresponding short option, and the option 60structure is only used to translate from long options to short 61options. When used in this fashion, 62.Fn getopt_long 63behaves identically to 64.Xr getopt 3 . 65This is a good way to add long option processing to an existing program 66with the minimum of rewriting. 67.Pp 68In the second mechanism, a long option sets a flag in the 69.Fa option 70structure passed, or will store a pointer to the command line argument 71in the 72.Fa option 73structure passed to it for options that take arguments. Additionally, 74the long option's argument may be specified as a single argument with 75an equal sign, e.g. 76.Bd -literal 77myprogram --myoption=somevalue 78.Ed 79.Pp 80When a long option is processed the call to 81.Fn getopt_long 82will return 0. For this reason, long option processing without 83shortcuts is not backwards compatible with 84.Xr getopt 3 . 85.Pp 86It is possible to combine these methods, providing for long options 87processing with short option equivalents for some options. Less 88frequently used options would be processed as long options only. 89.Pp 90The 91.Fn getopt_long 92call requires a structure to be initialized describing the long 93options. The structure is: 94.Bd -literal 95struct option { 96 char *name; 97 int has_arg; 98 int *flag; 99 int val; 100}; 101.Ed 102.Pp 103The 104.Fa name 105field should contain the option name without the leading double dash. 106.Pp 107The 108.Fa has_arg 109field should be one of: 110.Bl -tag -width "optional_argument" 111.It Li no_argument 112no argument to the option is expect. 113.It Li required_argument 114an argument to the option is required. 115.It Li optional_argument 116an argument to the option may be presented. 117.El 118.Pp 119If 120.Fa flag 121is non-NULL, then the integer pointed to by it will be set to the 122value in the 123.Fa val 124field. If the 125.Fa flag 126field is NULL, then the 127.Fa val 128field will be returned. Setting 129.Fa flag 130to NULL and setting 131.Fa val 132to the corresponding short option will make this function act just 133like 134.Xr getopt 3 . 135.Sh EXAMPLES 136.Bd -literal -compact 137extern char *optarg; 138extern int optind; 139int bflag, ch, fd; 140int daggerset; 141 142/* options descriptor */ 143static struct option longopts[] = { 144 { "buffy", no_argument, 0, 'b' }, 145 { "floride", required_argument, 0, 'f' }, 146 { "daggerset", no_argument, \*[Am]daggerset, 1 }, 147 { 0, 0, 0, 0 } 148}; 149 150bflag = 0; 151while ((ch = getopt_long(argc, argv, "bf:", longopts, NULL)) != -1) 152 switch(ch) { 153 case 'b': 154 bflag = 1; 155 break; 156 case 'f': 157 if ((fd = open(optarg, O_RDONLY, 0)) \*[Lt] 0) { 158 (void)fprintf(stderr, 159 "myname: %s: %s\en", optarg, strerror(errno)); 160 exit(1); 161 } 162 break; 163 case 0: 164 if(daggerset) { 165 fprintf(stderr,"Buffy will use her dagger to " 166 "apply floride to dracula's teeth\en"); 167 } 168 break; 169 case '?': 170 default: 171 usage(); 172} 173argc -= optind; 174argv += optind; 175.Ed 176.Sh IMPLEMENTATION DIFFERENCES 177This section describes differences to the GNU implementation 178found in glibc-2.1.3: 179.Bl -tag -width "xxx" 180.It Li o 181handling of - as first char of option string in presence of 182environment variable POSIXLY_CORRECT: 183.Bl -tag -width "NetBSD" 184.It Li GNU 185ignores POSIXLY_CORRECT and returns non-options as 186arguments to option '\e1'. 187.It Li NetBSD 188honors POSIXLY_CORRECT and stops at the first non-option. 189.El 190.It Li o 191handling of :: in options string in presence of POSIXLY_CORRECT: 192.Bl -tag -width "NetBSD" 193.It Li Both 194GNU and NetBSD ignore POSIXLY_CORRECT here and take :: to 195mean the preceding option takes an optional argument. 196.El 197.It Li o 198return value in case of missing argument if first character 199(after + or -) in option string is not ':': 200.Bl -tag -width "NetBSD" 201.It Li GNU 202returns '?' 203.It NetBSD 204returns ':' (since NetBSD's getopt does). 205.El 206.It Li o 207handling of --a in getopt: 208.Bl -tag -width "NetBSD" 209.It Li GNU 210parses this as option '-', option 'a'. 211.It Li NetBSD 212parses this as '--', and returns -1 (ignoring the a). (Because 213the original getopt does.) 214.El 215.It Li o 216setting of optopt for long options with flag != NULL: 217.Bl -tag -width "NetBSD" 218.It Li GNU 219sets optopt to val. 220.It Li NetBSD 221sets optopt to 0 (since val would never be returned). 222.El 223.It Li o 224handling of -W with W; in option string in getopt (not getopt_long): 225.Bl -tag -width "NetBSD" 226.It Li GNU 227causes a segfault. 228.It Li NetBSD 229returns -1, with optind pointing past the argument of -W 230(as if `-W arg' were `--arg', and thus '--' had been found). 231.\" How should we treat W; in the option string when called via 232.\" getopt? Ignore the ';' or treat it as a ':'? Issue a warning? 233.El 234.It Li o 235setting of optarg for long options without an argument that are 236invoked via -W (W; in option string): 237.Bl -tag -width "NetBSD" 238.It Li GNU 239sets optarg to the option name (the argument of -W). 240.It Li NetBSD 241sets optarg to NULL (the argument of the long option). 242.El 243.It Li o 244handling of -W with an argument that is not (a prefix to) a known 245long option (W; in option string): 246.Bl -tag -width "NetBSD" 247.It Li GNU 248returns -W with optarg set to the unknown option. 249.It Li NetBSD 250treats this as an error (unknown option) and returns '?' with 251optopt set to 0 and optarg set to NULL (as GNU's man page 252documents). 253.El 254.It Li o 255The error messages are different. 256.It Li o 257NetBSD does not permute the argument vector at the same points in 258the calling sequence as GNU does. The aspects normally used by 259the caller (ordering after -1 is returned, value of optind relative 260to current positions) are the same, though. (We do fewer variable 261swaps.) 262.El 263.Sh SEE ALSO 264.Xr getopt 3 265.Sh HISTORY 266The 267.Fn getopt_long 268function first appeared in GNU libiberty. The first 269.Nx 270implementation appeared in 1.5. 271.Sh BUGS 272The implementation, can completelely replace 273.Xr getopt 3 , 274but right now we are using separate code. 275