stdio/vsprintf.c

   1 /* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <limits.h>
  22 #include <stdarg.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25
  26
  27 /* Write formatted output to S according to the format string
  28    FORMAT, using the argument list in ARG.  */
  29 int
  30 DEFUN(vsprintf, (s, format, arg),
  31       char *s AND CONST char *format AND va_list arg)
  32 {
  33   int done;
  34   FILE f;
  35
  36   memset((PTR) &f, 0, sizeof(f));
  37   f.__magic = _IOMAGIC;
  38   f.__mode.__write = 1;
  39   f.__bufp = f.__buffer = (char *) s;
  40   f.__put_limit = (char *) ULONG_MAX;
  41   f.__bufsize = (size_t) (f.__put_limit - f.__bufp);
  42   f.__get_limit = f.__buffer;
  43   f.__room_funcs.__output = NULL;
  44   f.__seen = 1;
  45
  46   done = vfprintf(&f, format, arg);
  47   *f.__bufp = '\0';
  48
  49   return done;
  50 }