stdio/vsprintf.c

   1 /* Copyright (C) 1991, 1992, 1997 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <limits.h>
  21 #include <stdarg.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24
  25
  26 /* Write formatted output to S according to the format string
  27    FORMAT, using the argument list in ARG.  */
  28 int
  29 vsprintf (s, format, arg)
  30      char *s;
  31      const char *format;
  32      va_list arg;
  33 {
  34   int done;
  35   FILE f;
  36
  37   memset ((void *) &f, 0, sizeof (f));
  38   f.__magic = _IOMAGIC;
  39   f.__mode.__write = 1;
  40   f.__bufp = f.__buffer = (char *) s;
  41   f.__put_limit = (char *) ULONG_MAX;
  42   f.__bufsize = (size_t) (f.__put_limit - f.__bufp);
  43   f.__get_limit = f.__buffer;
  44   f.__room_funcs.__output = NULL;
  45   f.__seen = 1;
  46
  47   done = vfprintf (&f, format, arg);
  48   *f.__bufp = '\0';
  49
  50   return done;
  51 }