1 /* realloc() function that is glibc compatible.
2
3 Copyright (C) 1997, 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18 /* written by Jim Meyering and Bruno Haible */
19
20 #include <config.h>
21
22 /* Only the AC_FUNC_REALLOC macro defines 'realloc' already in config.h. */
23 #ifdef realloc
24 # define NEED_REALLOC_GNU 1
25 #endif
26
27 /* Infer the properties of the system's malloc function.
28 Only the AC_FUNC_MALLOC macro defines 'malloc' already in config.h. */
29 #if GNULIB_MALLOC_GNU && !defined malloc
30 # define SYSTEM_MALLOC_GLIBC_COMPATIBLE 1
31 #endif
32
33 /* Below we want to call the system's malloc and realloc.
34 Undefine the symbols here so that including <stdlib.h> provides a
35 declaration of malloc(), not of rpl_malloc(), and likewise for realloc. */
36 #undef malloc
37 #undef realloc
38
39 /* Specification. */
40 #include <stdlib.h>
41
42 #include <errno.h>
43
44 /* Below we want to call the system's malloc and realloc.
45 Undefine the symbols, if they were defined by gnulib's <stdlib.h>
46 replacement. */
47 #undef malloc
48 #undef realloc
49
50 /* Change the size of an allocated block of memory P to N bytes,
51 with error checking. If N is zero, change it to 1. If P is NULL,
52 use malloc. */
53
54 void *
rpl_realloc(void * p,size_t n)55 rpl_realloc (void *p, size_t n)
56 {
57 void *result;
58
59 #if NEED_REALLOC_GNU
60 if (n == 0)
61 {
62 n = 1;
63
64 /* In theory realloc might fail, so don't rely on it to free. */
65 free (p);
66 p = NULL;
67 }
68 #endif
69
70 if (p == NULL)
71 {
72 #if GNULIB_REALLOC_GNU && !NEED_REALLOC_GNU && !SYSTEM_MALLOC_GLIBC_COMPATIBLE
73 if (n == 0)
74 n = 1;
75 #endif
76 result = malloc (n);
77 }
78 else
79 result = realloc (p, n);
80
81 #if !HAVE_REALLOC_POSIX
82 if (result == NULL)
83 errno = ENOMEM;
84 #endif
85
86 return result;
87 }
88