lib/realloc.c

   1 /* realloc() function that is glibc compatible.
   2
   3    Copyright (C) 1997, 2003-2004, 2006-2007, 2009-2024 Free Software
   4    Foundation, Inc.
   5
   6    This file is free software: you can redistribute it and/or modify
   7    it under the terms of the GNU Lesser General Public License as
   8    published by the Free Software Foundation; either version 2.1 of the
   9    License, or (at your option) any later version.
  10
  11    This file is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public License
  17    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  18
  19 /* written by Jim Meyering and Bruno Haible */
  20
  21 #include <config.h>
  22
  23 #include <stdlib.h>
  24
  25 #include <errno.h>
  26
  27 #include "xalloc-oversized.h"
  28
  29 /* Call the system's realloc below.  This file does not define
  30    _GL_USE_STDLIB_ALLOC because it needs Gnulib's malloc if present.  */
  31 #undef realloc
  32
  33 /* Change the size of an allocated block of memory P to N bytes,
  34    with error checking.  If P is NULL, use malloc.  Otherwise if N is zero,
  35    free P and return NULL.  */
  36
  37 void *
  38 rpl_realloc (void *p, size_t n)
  39 {
  40   if (p == NULL)
  41     return malloc (n);
  42
  43   if (n == 0)
  44     {
  45       free (p);
  46       return NULL;
  47     }
  48
  49   if (xalloc_oversized (n, 1))
  50     {
  51       errno = ENOMEM;
  52       return NULL;
  53     }
  54
  55   void *result = realloc (p, n);
  56
  57 #if !HAVE_MALLOC_POSIX
  58   if (result == NULL)
  59     errno = ENOMEM;
  60 #endif
  61
  62   return result;
  63 }