blob: d447cc2d56044e70ccbd349664ba4fd6fa2c57ca [file] [log] [blame]
/* Formatted output to strings.
Copyright (C) 2004, 2006-2010 Free Software Foundation, Inc.
Written by Simon Josefsson and Yoann Vandoorselaere <>.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
# include <config.h>
/* Specification. */
#include <stdio.h>
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include "vasnprintf.h"
/* Print formatted output to string STR. Similar to vsprintf, but
additional length SIZE limit how much is written into STR. Returns
string length of formatted string (which may be larger than SIZE).
STR may be NULL, in which case nothing will be written. On error,
return a negative value. */
vsnprintf (char *str, size_t size, const char *format, va_list args)
char *output;
size_t len;
size_t lenbuf = size;
output = vasnprintf (str, &lenbuf, format, args);
len = lenbuf;
if (!output)
return -1;
if (output != str)
if (size)
size_t pruned_len = (len < size ? len : size - 1);
memcpy (str, output, pruned_len);
str[pruned_len] = '\0';
free (output);
if (len > INT_MAX)
errno = EOVERFLOW;
return -1;
return len;