1/* Internal declarations for malloc, for use within libc.
2 Copyright (C) 2016-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If
17 not, see <https://www.gnu.org/licenses/>. */
18
19#ifndef _MALLOC_INTERNAL_H
20#define _MALLOC_INTERNAL_H
21
22#include <malloc-machine.h>
23#include <malloc-sysdep.h>
24
25/* INTERNAL_SIZE_T is the word-size used for internal bookkeeping of
26 chunk sizes.
27
28 The default version is the same as size_t.
29
30 While not strictly necessary, it is best to define this as an
31 unsigned type, even if size_t is a signed type. This may avoid some
32 artificial size limitations on some systems.
33
34 On a 64-bit machine, you may be able to reduce malloc overhead by
35 defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' at the
36 expense of not being able to handle more than 2^32 of malloced
37 space. If this limitation is acceptable, you are encouraged to set
38 this unless you are on a platform requiring 16byte alignments. In
39 this case the alignment requirements turn out to negate any
40 potential advantages of decreasing size_t word size.
41
42 Implementors: Beware of the possible combinations of:
43 - INTERNAL_SIZE_T might be signed or unsigned, might be 32 or 64 bits,
44 and might be the same width as int or as long
45 - size_t might have different width and signedness as INTERNAL_SIZE_T
46 - int and long might be 32 or 64 bits, and might be the same width
47
48 To deal with this, most comparisons and difference computations
49 among INTERNAL_SIZE_Ts should cast them to unsigned long, being
50 aware of the fact that casting an unsigned int to a wider long does
51 not sign-extend. (This also makes checking for negative numbers
52 awkward.) Some of these casts result in harmless compiler warnings
53 on some systems. */
54#ifndef INTERNAL_SIZE_T
55# define INTERNAL_SIZE_T size_t
56#endif
57
58/* The corresponding word size. */
59#define SIZE_SZ (sizeof (INTERNAL_SIZE_T))
60
61/* The corresponding bit mask value. */
62#define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
63
64
65/* Called in the parent process before a fork. */
66void __malloc_fork_lock_parent (void) attribute_hidden;
67
68/* Called in the parent process after a fork. */
69void __malloc_fork_unlock_parent (void) attribute_hidden;
70
71/* Called in the child process after a fork. */
72void __malloc_fork_unlock_child (void) attribute_hidden;
73
74/* Called as part of the thread shutdown sequence. */
75void __malloc_arena_thread_freeres (void) attribute_hidden;
76
77/* Activate a standard set of debugging hooks. */
78void __malloc_check_init (void) attribute_hidden;
79
80#endif /* _MALLOC_INTERNAL_H */
81