src/lib9/fmt/vsnprint.c

/*
 * The authors of this software are Rob Pike and Ken Thompson,
 * with contributions from Mike Burrows and Sean Dorward.
 *
 *     Copyright (c) 2002-2006 by Lucent Technologies.
 *     Portions Copyright (c) 2004 Google Inc.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose without fee is hereby granted, provided that this entire notice
 * is included in all copies of any software which is or includes a copy
 * or modification of this software and in all copies of the supporting
 * documentation for such software.
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES 
 * NOR GOOGLE INC MAKE ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING 
 * THE MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 */

#include <u.h>
#include <libc.h>
#include "fmtdef.h"

int
vsnprint(char *buf, int len, char *fmt, va_list args)
{
	Fmt f;

	if(len <= 0)
		return -1;
	f.runes = 0;
	f.start = buf;
	f.to = buf;
	f.stop = buf + len - 1;
	f.flush = 0;
	f.farg = nil;
	f.nfmt = 0;
	VA_COPY(f.args,args);
	fmtlocaleinit(&f, nil, nil, nil);
	dofmt(&f, fmt);
	VA_END(f.args);
	*(char*)f.to = '\0';
	return (char*)f.to - buf;
}