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From: schwartz@uw-june (Michael Schwartz)
Newsgroups: net.sources
Subject: getopt
Message-ID: <346@uw-june>
Date: Tue, 8-Oct-85 17:32:25 EDT
Article-I.D.: uw-june.346
Posted: Tue Oct 8 17:32:25 1985
Date-Received: Fri, 11-Oct-85 06:51:18 EDT
Organization: U of Washington Computer Science
Lines: 357
There has been a fair amount of software posted on the net which uses getopt,
but it took me a while to track down a copy of getopt for myself. Here it is,
including the manpage. The manpage output (as well as source) is included for
systems which can't process the manpage source.
--------------------------------- cut here ------------------------------------
############################################################
#
# getopt.ar
#
# To extract the files from this shell archive file
# simply create a directory for this file
# and move the archive file to it
# and enter the command
#
# sh filename.ar
#
# Do not use csh
# The files will be extracted automatically
#
############################################################
echo "Extracting getopt.3c <-- getopt.ar"
cat << \===getopt.3c=== > getopt.3c
.\" @(#)getopt.3c 1.1 83/08/30 SMI; from UCB 4.2
.TH GETOPT 3C "26 August 1983"
.SH NAME
getopt, optarg, optind \- get option letter from argv
.SH SYNOPSIS
.nf
.ft B
int getopt(argc, argv, optstring)
int args;
char **argv;
char *optstring;
.ft P
.LP
.ft B
extern char *optarg;
extern int optind;
.ft R
.fi
.SH DESCRIPTION
.ft B
This routine is included for compatibility with UNIX system-III.
It is of marginal value, and should not be used in new programs.
.ft R
.LP
.I Getopt
returns the next option letter in
.I argv
that matches a letter in
.I optstring.
.I Optstring
is a string of recognized option letters; if a letter is followed
by a colon, the option is expected to have an argument that may
or may not be separated from it by white space.
.I Optarg
is set to point to the start of the option argument on return
from
.I getopt.
.LP
.I Getopt
places in
.I optind
the
.I argv
index of the next argument to be processed.
Because
.I optind
is external, it is normally initialized to zero automatically before
the first call to
.I getopt.
.LP
When all options have been processed (i.e., up to the first non-option
argument),
.I getopt
returns
.B \s-2EOF\s0.
The special option \-\- may be used to delimit the end
of the options;
.B \s-2EOF\s0
will be returned, and \-\- will be skipped.
.SH DIAGNOSTICS
.I Getopt
prints an error message on
.I stderr
and returns a question mark (?)
when it encounters an option letter not included in
.I optstring.
.SH EXAMPLE
The following code fragment shows how one might process the arguments for a
command that can take the mutually exclusive options
.B a
and
.B b,
and the options
.B f
and
.B o,
both of which require arguments:
.LP
.nf
.DT
main(argc, argv)
int argc;
char **argv;
{
int c;
extern int optind;
extern char *optarg;
\&\fB.\fP
\&\fB.\fP
\&\fB.\fP
while ((c = getopt(argc, argv, "abf:o:")) != EOF)
switch (c) {
case 'a':
if (bflg)
errflg++;
else
aflg++;
break;
case 'b':
if (aflg)
errflg++;
else
bproc();
break;
case 'f':
infile = optarg;
break;
case 'o':
ofile = optarg;
bufsiza = 512;
break;
case '?':
errflg++;
}
if (errflg) {
fprintf(stderr, "usage: . . . ");
exit(2);
}
for (; optind < argc; optind++) {
if (access(argv[optind], 4)) {
\&\fB.\fP
\&\fB.\fP
\&\fB.\fP
}
.fi
===getopt.3c===
# ----------
echo "Extracting getopt.c <-- getopt.ar"
cat << \===getopt.c=== > getopt.c
/*
* getopt - get option letter from argv
*/
#include <stdio.h>
char *optarg; /* Global argument pointer. */
int optind = 0; /* Global argv index. */
static char *scan = NULL; /* Private scan pointer. */
extern char *index();
int
getopt(argc, argv, optstring)
int argc;
char *argv[];
char *optstring;
{
register char c;
register char *place;
optarg = NULL;
if (scan == NULL || *scan == '\0') {
if (optind == 0)
optind++;
if (optind >= argc || argv[optind][0] != '-' || argv[optind][1] == '\0')
return(EOF);
if (strcmp(argv[optind], "--")==0) {
optind++;
return(EOF);
}
scan = argv[optind]+1;
optind++;
}
c = *scan++;
place = index(optstring, c);
if (place == NULL || c == ':') {
fprintf(stderr, "%s: unknown option -%c\n", argv[0], c);
return('?');
}
place++;
if (*place == ':') {
if (*scan != '\0') {
optarg = scan;
scan = NULL;
} else if (optind < argc) {
optarg = argv[optind];
optind++;
} else {
fprintf(stderr, "%s: -%c argument missing\n", argv[0], c);
return('?');
}
}
return(c);
}
===getopt.c===
# ----------
echo "Extracting getopt.manpage <-- getopt.ar"
cat << \===getopt.manpage=== > getopt.manpage
GETOPT(3C) UNIX Programmer's Manual GETOPT(3C)
NAME
getopt, optarg, optind - get option letter from argv
SYNOPSIS
int getopt(argc, argv, optstring)
int args;
char **argv;
char *optstring;
extern char *optarg;
extern int optind;
DESCRIPTION
This routine is included for compatibility with UNIX
system-III. It is of marginal value, and should not be used
in new programs.
_G_e_t_o_p_t returns the next option letter in _a_r_g_v that matches a
letter in _o_p_t_s_t_r_i_n_g. _O_p_t_s_t_r_i_n_g is a string
of recognized
option letters; if a letter is followed by a colon, the
option is expected to have an argument that may or may not
be separated from it by white space. _O_p_t_a_r_g is set to point
to the start of the option argument on return from _g_e_t_o_p_t.
_G_e_t_o_p_t places in _o_p_t_i_n_d the _a_r_g_v index of the
next argument
to be processed. Because _o_p_t_i_n_d is external, it is normally
initialized to zero automatically before the first call to
_g_e_t_o_p_t.
When all options have been processed (i.e., up to the first
non-option argument), _g_e_t_o_p_t returns EOF. The special option
-- may be used to delimit the end of the options; EOF will
be returned, and -- will be skipped.
DIAGNOSTICS
_G_e_t_o_p_t prints an error message on _s_t_d_e_r_r and returns a ques-
tion mark (?) when it encounters an option letter not
included in _o_p_t_s_t_r_i_n_g.
EXAMPLE
The following code fragment shows how one might process the
arguments for a command that can take the mutually exclusive
options a and b, and the options f and o, both of which
require arguments:
main(argc, argv)
int argc;
char **argv;
{
int c;
extern int optind;
extern char *optarg;
Printed 10/8/85 26 August 1983 1
GETOPT(3C) UNIX Programmer's Manual GETOPT(3C)
.
.
.
while ((c = getopt(argc, argv, "abf:o:")) != EOF)
switch (c) {
case 'a':
if (bflg)
errflg++;
else
aflg++;
break;
case 'b':
if (aflg)
errflg++;
else
bproc();
break;
case 'f':
infile = optarg;
break;
case 'o':
ofile = optarg;
bufsiza = 512;
break;
case '?':
errflg++;
}
if (errflg) {
fprintf(stderr, "usage: . . . ");
exit(2);
}
for (; optind < argc; optind++) {
if (access(argv[optind], 4)) {
.
.
.
}
Printed 10/8/85 26 August 1983 2
===getopt.manpage===
# ----------
|