xref: /inferno-os/libkern/vsnprint.c (revision 7ef44d652ae9e5e1f5b3465d73684e4a54de73c0)
1 /*
2  * The authors of this software are Rob Pike and Ken Thompson.
3  *              Copyright (c) 2002 by Lucent Technologies.
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose without fee is hereby granted, provided that this entire notice
6  * is included in all copies of any software which is or includes a copy
7  * or modification of this software and in all copies of the supporting
8  * documentation for such software.
9  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
11  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13  */
14 #include "lib9.h"
15 #include "fmtdef.h"
16 
17 int
18 vsnprint(char *buf, int len, char *fmt, va_list args)
19 {
20 	Fmt f;
21 
22 	if(len <= 0)
23 		return -1;
24 	f.runes = 0;
25 	f.start = buf;
26 	f.to = buf;
27 	f.stop = buf + len - 1;
28 	f.flush = nil;
29 	f.farg = nil;
30 	f.nfmt = 0;
31 	va_copy(f.args, args);
32 	dofmt(&f, fmt);
33 	va_end(f.args);
34 	*(char*)f.to = '\0';
35 	return (char*)f.to - buf;
36 }
37