xref: /original-bsd/lib/libc/stdlib/getopt.c (revision 53787e02)
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 #ifndef lint
8 static char sccsid[] = "@(#)getopt.c	4.1 (Berkeley) 05/30/85";
9 #endif not lint
10 
11 #include <stdio.h>
12 
13 /*
14  * get option letter from argument vector
15  */
16 int	opterr = 1,		/* useless, never set or used */
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)	fputs(*nargv,stderr);fputs(s,stderr); \
24 		fputc(optopt,stderr);fputc('\n',stderr);return(BADCH);
25 
26 getopt(nargc,nargv,ostr)
27 int	nargc;
28 char	**nargv,
29 	*ostr;
30 {
31 	static char	*place = EMSG;	/* option letter processing */
32 	register char	*oli;		/* option letter list index */
33 	char	*index();
34 
35 	if(!*place) {			/* update scanning pointer */
36 		if(optind >= nargc || *(place = nargv[optind]) != '-' || !*++place) return(EOF);
37 		if (*place == '-') {	/* found "--" */
38 			++optind;
39 			return(EOF);
40 		}
41 	}				/* option letter okay? */
42 	if ((optopt = (int)*place++) == (int)':' || !(oli = index(ostr,optopt))) {
43 		if(!*place) ++optind;
44 		tell(": illegal option -- ");
45 	}
46 	if (*++oli != ':') {		/* don't need argument */
47 		optarg = NULL;
48 		if (!*place) ++optind;
49 	}
50 	else {				/* need an argument */
51 		if (*place) optarg = place;	/* no white space */
52 		else if (nargc <= ++optind) {	/* no arg */
53 			place = EMSG;
54 			tell(": option requires an argument -- ");
55 		}
56 	 	else optarg = nargv[optind];	/* white space */
57 		place = EMSG;
58 		++optind;
59 	}
60 	return(optopt);			/* dump back option letter */
61 }
62