xref: /titanic_50/usr/src/lib/libast/common/stdio/vsnprintf.c (revision 3db3491215579980a91e230cf21b20608fbb8259)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *          Copyright (c) 1985-2008 AT&T Intellectual Property          *
5 *                      and is licensed under the                       *
6 *                  Common Public License, Version 1.0                  *
7 *                    by AT&T Intellectual Property                     *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #pragma prototyped
23 
24 #include "stdhdr.h"
25 
26 int
27 vsnprintf(char* s, int n, const char* fmt, va_list args)
28 {
29 	Sfio_t	f;
30 	int	v;
31 
32 	if (!s)
33 		return -1;
34 
35 	/*
36 	 * make a fake stream
37 	 */
38 
39 	SFCLEAR(&f, NiL);
40 	f.flags = SF_STRING|SF_WRITE;
41 	f.bits = SF_PRIVATE;
42 	f.mode = SF_WRITE;
43 	f.size = n - 1;
44 	f.data = f.next = f.endr = (uchar*)s;
45 	f.endb = f.endw = f.data + f.size;
46 
47 	/*
48 	 * call and fix up
49 	 */
50 
51 	v = sfvprintf(&f, fmt, args);
52 	*f.next = 0;
53 	_Sfi = f.next - f.data;
54 	return v;
55 }
56