.\" (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" License. .\" Modified Sat Jul 24 19:27:50 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Mon Aug 30 22:02:34 1995 by Jim Van Zandt .\" longindex is a pointer, has_arg can take 3 values, using consistent .\" names for optstring and longindex, "\n" in formats fixed. Documenting .\" opterr and getopt_long_only. Clarified explanations (borrowing heavily .\" from the source code). .\" Modified 8 May 1998 by Joseph S. Myers (jsm28@cam.ac.uk) .\" Modified 990715, aeb: changed `EOF' into `-1' since that is what POSIX .\" says; moreover, EOF is not defined in . .\" .TH GETOPT 3 "8 May 1998" "GNU" "Linux Programmer's Manual" .SH NAME getopt \- Parse command line options .SH SYNOPSIS .nf .B #include .sp .BI "int getopt(int " argc ", char * const " argv[] "," .BI " const char *" optstring ");" .sp .BI "extern char *" optarg ; .BI "extern int " optind ", " opterr ", " optopt ; .sp .B #define _GNU_SOURCE .br .B #include .sp .BI "int getopt_long(int " argc ", char * const " argv[] ", .BI " const char *" optstring , .BI " const struct option *" longopts ", int *" longindex ");" .sp .BI "int getopt_long_only(int " argc ", char * const " argv[] ", .BI " const char *" optstring , .BI " const struct option *" longopts ", int *" longindex ");" .fi .SH DESCRIPTION The .B getopt() function parses the command line arguments. Its arguments .I argc and .I argv are the argument count and array as passed to the .B main() function on program invocation. An element of \fIargv\fP that starts with `-' (and is not exactly "-" or "--") is an option element. The characters of this element (aside from the initial `-') are option characters. If \fBgetopt()\fP is called repeatedly, it returns successively each of the option characters from each of the option elements. .PP If \fBgetopt()\fP finds another option character, it returns that character, updating the external variable \fIoptind\fP and a static variable \fInextchar\fP so that the next call to \fBgetopt()\fP can resume the scan with the following option character or \fIargv\fP-element. .PP If there are no more option characters, \fBgetopt()\fP returns \-1. Then \fIoptind\fP is the index in \fIargv\fP of the first \fIargv\fP-element that is not an option. .PP .I optstring is a string containing the legitimate option characters. If such a character is followed by a colon, the option requires an argument, so \fBgetopt\fP places a pointer to the following text in the same \fIargv\fP-element, or the text of the following \fIargv\fP-element, in .IR optarg . Two colons mean an option takes an optional arg; if there is text in the current \fIargv\fP-element, it is returned in \fIoptarg\fP, otherwise \fIoptarg\fP is set to zero. This is a GNU extension. If .I optstring contains .B W followed by a semicolon, then .B -W foo is treated as the long option .BR --foo . (The .B -W option is reserved by POSIX.2 for implementation extensions.) This behaviour is a GNU extension, not available with libraries before GNU libc 2. .PP By default, \fBgetopt()\fP permutes the contents of \fIargv\fP as it scans, so that eventually all the non-options are at the end. Two other modes are also implemented. If the first character of \fIoptstring\fP is `+' or the environment variable POSIXLY_CORRECT is set, then option processing stops as soon as a non-option argument is encountered. If the first character of \fIoptstring\fP is `-', then each non-option \fIargv\fP-element is handled as if it were the argument of an option with character code 1. (This is used by programs that were written to expect options and other \fIargv\fP-elements in any order and that care about the ordering of the two.) The special argument `--' forces an end of option-scanning regardless of the scanning mode. .PP If \fBgetopt()\fP does not recognize an option character, it prints an error message to stderr, stores the character in \fIoptopt\fP, and returns `?'. The calling program may prevent the error message by setting \fIopterr\fP to 0. .PP The .B getopt_long() function works like .B getopt() except that it also accepts long options, started out by two dashes. Long option names may be abbreviated if the abbreviation is unique or is an exact match for some defined option. A long option may take a parameter, of the form .B --arg=param or .BR "--arg param" . .PP .I longopts is a pointer to the first element of an array of .B struct option declared in .B as .nf .sp .in 10 struct option { .in 14 const char *name; int has_arg; int *flag; int val; .in 10 }; .fi .PP The meanings of the different fields are: .TP .I name is the name of the long option. .TP .I has_arg is: \fBno_argument\fP (or 0) if the option does not take an argument, \fBrequired_argument\fP (or 1) if the option requires an argument, or \fBoptional_argument\fP (or 2) if the option takes an optional argument. .TP .I flag specifies how results are returned for a long option. If \fIflag\fP is \fBNULL\fP, then \fBgetopt_long()\fP returns \fIval\fP. (For example, the calling program may set \fIval\fP to the equivalent short option character.) Otherwise, \fBgetopt_long()\fP returns 0, and \fIflag\fP points to a variable which is set to \fIval\fP if the option is found, but left unchanged if the option is not found. .TP \fIval\fP is the value to return, or to load into the variable pointed to by \fIflag\fP. .PP The last element of the array has to be filled with zeroes. .PP If \fIlongindex\fP is not \fBNULL\fP, it points to a variable which is set to the index of the long option relative to .IR longopts . .PP \fBgetopt_long_only()\fP is like \fBgetopt_long()\fP, but `-' as well as `--' can indicate a long option. If an option that starts with `-' (not `--') doesn't match a long option, but does match a short option, it is parsed as a short option instead. .SH "RETURN VALUE" The .B getopt() function returns the option character if the option was found successfully, `:' if there was a missing parameter for one of the options, `?' for an unknown option character, or \-1 for the end of the option list. .PP \fBgetopt_long()\fP and \fBgetopt_long_only()\fP also return the option character when a short option is recognized. For a long option, they return \fIval\fP if \fIflag\fP is \fBNULL\fP, and 0 otherwise. Error and \-1 returns are the same as for \fBgetopt()\fP, plus `?' for an ambiguous match or an extraneous parameter. .SH "ENVIRONMENT VARIABLES" .TP .SM .B POSIXLY_CORRECT If this is set, then option processing stops as soon as a non-option argument is encountered. .TP .SM .B __GNU_nonoption_argv_flags_ This variable was used by .B bash 2.0 to communicate to GNU libc which arguments are the results of wildcard expansion and so should not be considered as options. This behaviour was removed in .B bash version 2.01, but the support remains in GNU libc. .SH "EXAMPLE" The following example program, from the source code, illustrates the use of .BR getopt_long() with most of its features. .nf .sp #include int main (argc, argv) int argc; char **argv; { int c; int digit_optind = 0; while (1) { int this_option_optind = optind ? optind : 1; int option_index = 0; static struct option long_options[] = { {"add", 1, 0, 0}, {"append", 0, 0, 0}, {"delete", 1, 0, 0}, {"verbose", 0, 0, 0}, {"create", 1, 0, 'c'}, {"file", 1, 0, 0}, {0, 0, 0, 0} }; c = getopt_long (argc, argv, "abc:d:012", long_options, &option_index); if (c == -1) break; switch (c) { case 0: printf ("option %s", long_options[option_index].name); if (optarg) printf (" with arg %s", optarg); printf ("\\n"); break; case '0': case '1': case '2': if (digit_optind != 0 && digit_optind != this_option_optind) printf ("digits occur in two different argv-elements.\\n"); digit_optind = this_option_optind; printf ("option %c\\n", c); break; case 'a': printf ("option a\\n"); break; case 'b': printf ("option b\\n"); break; case 'c': printf ("option c with value `%s'\\n", optarg); break; case 'd': printf ("option d with value `%s'\\n", optarg); break; case '?': break; default: printf ("?? getopt returned character code 0%o ??\\n", c); } } if (optind < argc) { printf ("non-option ARGV-elements: "); while (optind < argc) printf ("%s ", argv[optind++]); printf ("\\n"); } exit (0); } .fi .SH "BUGS" This manpage is confusing. .PP The POSIX.2 specification of .B getopt() has a technical error described in POSIX.2 Interpretation 150. The GNU implementation (and probably all other implementations) implements the correct behaviour rather than that specified. .SH "CONFORMING TO" .TP \fBgetopt()\fP: POSIX.2, provided the environment variable POSIXLY_CORRECT is set. Otherwise, the elements of \fIargv\fP aren't really const, because we permute them. We pretend they're const in the prototype to be compatible with other systems. .SH TRADUÇÃO PARA A LÍNGUA PORTUGUESA \&\fR\&\f(CWRUBENS DE JESUS NOGUEIRA (tradução)\fR \&\fR\&\f(CWXXXXXX XX XXXXX XXXXXXXX (revisão)\fR