xref: /csrg-svn/lib/libc/stdlib/getopt.c (revision 32111)
1 /*
2  * Copyright (c) 1985 Regents of the University of California.
3  * All rights reserved.  The Berkeley software License Agreement
4  * specifies the terms and conditions for redistribution.
5  */
6 
7 #if defined(LIBC_SCCS) && !defined(lint)
8 static char sccsid[] = "@(#)getopt.c	4.4 (Berkeley) 09/04/87";
9 #endif LIBC_SCCS and not lint
10 
11 #include <stdio.h>
12 
13 /*
14  * get option letter from argument vector
15  */
16 int	opterr = 1,		/* if error message should be printed */
17 	optind = 1,		/* index into parent argv vector */
18 	optopt;			/* character checked for validity */
19 char	*optarg;		/* argument associated with option */
20 
21 #define BADCH	(int)'?'
22 #define EMSG	""
23 #define tell(s)	{ \
24 	if (opterr) { \
25 		fputs(*nargv, stderr); \
26 		fputs(s, stderr); \
27 		fputc(optopt, stderr); \
28 		fputc((int)'\n', stderr); \
29 	} \
30 	return(BADCH); \
31 }
32 
33 getopt(nargc, nargv, ostr)
34 	int	nargc;
35 	char	**nargv, *ostr;
36 {
37 	static char	*place = EMSG;		/* option letter processing */
38 	register char	*oli;			/* option letter list index */
39 	char	*index();
40 
41 	if (!*place) {				/* update scanning pointer */
42 		if (optind >= nargc || *(place = nargv[optind]) != '-' ||
43 		    !*++place)
44 			return(EOF);
45 		if (*place == '-') {		/* found "--" */
46 			++optind;
47 			return(EOF);
48 		}
49 	}					/* option letter okay? */
50 	if ((optopt = (int)*place++) == (int)':' ||
51 	    !(oli = index(ostr, optopt))) {
52 		if (!*place)
53 			++optind;
54 		tell(": illegal option -- ");
55 	}
56 	if (*++oli != ':') {			/* don't need argument */
57 		optarg = NULL;
58 		if (!*place)
59 			++optind;
60 	}
61 	else {					/* need an argument */
62 		if (*place)			/* no white space */
63 			optarg = place;
64 		else if (nargc <= ++optind) {	/* no arg */
65 			place = EMSG;
66 			tell(": option requires an argument -- ");
67 		}
68 	 	else				/* white space */
69 			optarg = nargv[optind];
70 		place = EMSG;
71 		++optind;
72 	}
73 	return(optopt);				/* dump back option letter */
74 }
75