lib/fprintf.c

   1 /* Formatted output to a stream.
   2    Copyright (C) 2004, 2006-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation, either version 3 of the
   7    License, or (at your option) any later version.
   8
   9    This file 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
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #ifdef HAVE_CONFIG_H
  18 # include <config.h>
  19 #endif
  20
  21 /* Specification.  */
  22 #include <stdio.h>
  23
  24 #include <errno.h>
  25 #include <limits.h>
  26 #include <stdarg.h>
  27 #include <stdlib.h>
  28
  29 #include "fseterr.h"
  30 #include "vasnprintf.h"
  31
  32 /* Print formatted output to the stream FP.
  33    Return string length of formatted string.  On error, return a negative
  34    value.  */
  35 int
  36 fprintf (FILE *fp, const char *format, ...)
  37 {
  38   char buf[2000];
  39   char *output;
  40   size_t len;
  41   size_t lenbuf = sizeof (buf);
  42   va_list args;
  43
  44   va_start (args, format);
  45   output = vasnprintf (buf, &lenbuf, format, args);
  46   len = lenbuf;
  47   va_end (args);
  48
  49   if (!output)
  50     {
  51       fseterr (fp);
  52       return -1;
  53     }
  54
  55   if (fwrite (output, 1, len, fp) < len)
  56     {
  57       if (output != buf)
  58         free (output);
  59       return -1;
  60     }
  61
  62   if (output != buf)
  63     free (output);
  64
  65   if (len > INT_MAX)
  66     {
  67       errno = EOVERFLOW;
  68       fseterr (fp);
  69       return -1;
  70     }
  71
  72   return len;
  73 }