xref: /csrg-svn/lib/libc/stdlib/getopt.c (revision 34831)
1 /*
2  * Copyright (c) 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)getopt.c	4.7 (Berkeley) 06/27/88";
20 #endif /* LIBC_SCCS and not lint */
21 
22 #include <stdio.h>
23 
24 /*
25  * get option letter from argument vector
26  */
27 int	opterr = 1,		/* if error message should be printed */
28 	optind = 1,		/* index into parent argv vector */
29 	optopt;			/* character checked for validity */
30 char	*optarg;		/* argument associated with option */
31 
32 #define	BADCH	(int)'?'
33 #define	EMSG	""
34 #define	tell(s)	{ \
35 	if (opterr) { \
36 		fputs(*nargv, stderr); \
37 		fputs(s, stderr); \
38 		fputc(optopt, stderr); \
39 		fputc((int)'\n', stderr); \
40 	} \
41 	return(BADCH); \
42 }
43 
44 getopt(nargc, nargv, ostr)
45 	int nargc;
46 	char **nargv, *ostr;
47 {
48 	static char *place = EMSG;		/* option letter processing */
49 	register char *oli;			/* option letter list index */
50 	char *index();
51 
52 	if (!*place) {				/* update scanning pointer */
53 		if (optind >= nargc || *(place = nargv[optind]) != '-')
54 			return(EOF);
55 		if (place[1] && *++place == '-') {	/* found "--" */
56 			++optind;
57 			return(EOF);
58 		}
59 	}					/* option letter okay? */
60 	if ((optopt = (int)*place++) == (int)':' ||
61 	    !(oli = index(ostr, optopt))) {
62 		if (!*place)
63 			++optind;
64 		tell(": illegal option -- ");
65 	}
66 	if (*++oli != ':') {			/* don't need argument */
67 		optarg = NULL;
68 		if (!*place)
69 			++optind;
70 	}
71 	else {					/* need an argument */
72 		if (*place)			/* no white space */
73 			optarg = place;
74 		else if (nargc <= ++optind) {	/* no arg */
75 			place = EMSG;
76 			tell(": option requires an argument -- ");
77 		}
78 	 	else				/* white space */
79 			optarg = nargv[optind];
80 		place = EMSG;
81 		++optind;
82 	}
83 	return(optopt);				/* dump back option letter */
84 }
85