| [9] | 1 | .\" Copyright (c) 1985 Regents of the University of California.
|
|---|
| 2 | .\" All rights reserved. The Berkeley software License Agreement
|
|---|
| 3 | .\" specifies the terms and conditions for redistribution.
|
|---|
| 4 | .\"
|
|---|
| 5 | .\" @(#)getopt.3 6.4 (Berkeley) 5/27/86
|
|---|
| 6 | .\"
|
|---|
| 7 | .TH GETOPT 3 "May 27, 1986"
|
|---|
| 8 | .UC 6
|
|---|
| 9 | .SH NAME
|
|---|
| 10 | getopt \- get option letter from argv
|
|---|
| 11 | .SH SYNOPSIS
|
|---|
| 12 | .ft B
|
|---|
| 13 | int getopt(argc, argv, optstring)
|
|---|
| 14 | .br
|
|---|
| 15 | int argc;
|
|---|
| 16 | .br
|
|---|
| 17 | char **argv;
|
|---|
| 18 | .br
|
|---|
| 19 | char *optstring;
|
|---|
| 20 | .sp
|
|---|
| 21 | extern char *optarg;
|
|---|
| 22 | .br
|
|---|
| 23 | extern int optind;
|
|---|
| 24 | .ft
|
|---|
| 25 | .SH DESCRIPTION
|
|---|
| 26 | .I Getopt
|
|---|
| 27 | returns the next option letter in
|
|---|
| 28 | .I argv
|
|---|
| 29 | that matches a letter in
|
|---|
| 30 | .IR optstring .
|
|---|
| 31 | .I Optstring
|
|---|
| 32 | is a string of recognized option letters;
|
|---|
| 33 | if a letter is followed by a colon, the option is expected to have
|
|---|
| 34 | an argument that may or may not be separated from it by white space.
|
|---|
| 35 | .I Optarg
|
|---|
| 36 | is set to point to the start of the option argument on return from
|
|---|
| 37 | .IR getopt .
|
|---|
| 38 | .PP
|
|---|
| 39 | .I Getopt
|
|---|
| 40 | places in
|
|---|
| 41 | .I optind
|
|---|
| 42 | the
|
|---|
| 43 | .I argv
|
|---|
| 44 | index of the next argument to be processed.
|
|---|
| 45 | Because
|
|---|
| 46 | .I optind
|
|---|
| 47 | is external, it is normally initialized to zero automatically
|
|---|
| 48 | before the first call to
|
|---|
| 49 | .IR getopt .
|
|---|
| 50 | .PP
|
|---|
| 51 | When all options have been processed (i.e., up to the first
|
|---|
| 52 | non-option argument),
|
|---|
| 53 | .I getopt
|
|---|
| 54 | returns
|
|---|
| 55 | .BR EOF .
|
|---|
| 56 | The special option
|
|---|
| 57 | .B \-\-
|
|---|
| 58 | may be used to delimit the end of the options;
|
|---|
| 59 | .B EOF
|
|---|
| 60 | will be returned, and
|
|---|
| 61 | .B \-\-
|
|---|
| 62 | will be skipped.
|
|---|
| 63 | .SH DIAGNOSTICS
|
|---|
| 64 | .I Getopt
|
|---|
| 65 | prints an error message on
|
|---|
| 66 | .I stderr
|
|---|
| 67 | and returns a question mark
|
|---|
| 68 | .RB ( ? )
|
|---|
| 69 | when it encounters an option letter not included in
|
|---|
| 70 | .IR optstring .
|
|---|
| 71 | .SH EXAMPLE
|
|---|
| 72 | The following code fragment shows how one might process the arguments
|
|---|
| 73 | for a command that can take the mutually exclusive options
|
|---|
| 74 | .B a
|
|---|
| 75 | and
|
|---|
| 76 | .BR b ,
|
|---|
| 77 | and the options
|
|---|
| 78 | .B f
|
|---|
| 79 | and
|
|---|
| 80 | .BR o ,
|
|---|
| 81 | both of which require arguments:
|
|---|
| 82 | .PP
|
|---|
| 83 | .RS
|
|---|
| 84 | .nf
|
|---|
| 85 | main(argc, argv)
|
|---|
| 86 | int argc;
|
|---|
| 87 | char **argv;
|
|---|
| 88 | {
|
|---|
| 89 | int c;
|
|---|
| 90 | extern int optind;
|
|---|
| 91 | extern char *optarg;
|
|---|
| 92 | \&.
|
|---|
| 93 | \&.
|
|---|
| 94 | \&.
|
|---|
| 95 | while ((c = getopt(argc, argv, "abf:o:")) != EOF)
|
|---|
| 96 | switch (c) {
|
|---|
| 97 | case `a':
|
|---|
| 98 | if (bflg)
|
|---|
| 99 | errflg++;
|
|---|
| 100 | else
|
|---|
| 101 | aflg++;
|
|---|
| 102 | break;
|
|---|
| 103 | case `b':
|
|---|
| 104 | if (aflg)
|
|---|
| 105 | errflg++;
|
|---|
| 106 | else
|
|---|
| 107 | bproc();
|
|---|
| 108 | break;
|
|---|
| 109 | case `f':
|
|---|
| 110 | ifile = optarg;
|
|---|
| 111 | break;
|
|---|
| 112 | case `o':
|
|---|
| 113 | ofile = optarg;
|
|---|
| 114 | break;
|
|---|
| 115 | case `?':
|
|---|
| 116 | default:
|
|---|
| 117 | errflg++;
|
|---|
| 118 | break;
|
|---|
| 119 | }
|
|---|
| 120 | if (errflg) {
|
|---|
| 121 | fprintf(stderr, "Usage: ...");
|
|---|
| 122 | exit(2);
|
|---|
| 123 | }
|
|---|
| 124 | for (; optind < argc; optind++) {
|
|---|
| 125 | \&.
|
|---|
| 126 | \&.
|
|---|
| 127 | \&.
|
|---|
| 128 | }
|
|---|
| 129 | \&.
|
|---|
| 130 | \&.
|
|---|
| 131 | \&.
|
|---|
| 132 | }
|
|---|
| 133 | .RE
|
|---|
| 134 | .SH HISTORY
|
|---|
| 135 | Written by Henry Spencer, working from a Bell Labs manual page.
|
|---|
| 136 | Modified by Keith Bostic to behave more like the System V version.
|
|---|
| 137 | .SH BUGS
|
|---|
| 138 | It is not obvious how
|
|---|
| 139 | `\-'
|
|---|
| 140 | standing alone should be treated; this version treats it as
|
|---|
| 141 | a non-option argument, which is not always right.
|
|---|
| 142 | .PP
|
|---|
| 143 | Option arguments are allowed to begin with `\-';
|
|---|
| 144 | this is reasonable but reduces the amount of error checking possible.
|
|---|
| 145 | .PP
|
|---|
| 146 | .I Getopt
|
|---|
| 147 | is quite flexible but the obvious price must be paid: there is much
|
|---|
| 148 | it could do that it doesn't, like
|
|---|
| 149 | checking mutually exclusive options, checking type of
|
|---|
| 150 | option arguments, etc.
|
|---|
