libstdc++: cxxabi_tweaks.h Source File

libstdc++

cxxabi_tweaks.h
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1// Control various target specific ABI tweaks. Generic version.
2
3// Copyright (C) 2004-2026 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library 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 General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file bits/cxxabi_tweaks.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{cxxabi.h}
28 */
29
30#ifndef _CXXABI_TWEAKS_H
31#define _CXXABI_TWEAKS_H 1
32
33#ifdef __cplusplus
34namespace __cxxabiv1
35{
36 extern "C"
37 {
38#endif
39
40 // The generic ABI uses the first byte of a 64-bit guard variable.
41#define _GLIBCXX_GUARD_TEST(x) (*(char *) (x) != 0)
42#define _GLIBCXX_GUARD_SET(x) *(char *) (x) = 1
43#define _GLIBCXX_GUARD_BIT __guard_test_bit (0, 1)
44#define _GLIBCXX_GUARD_PENDING_BIT __guard_test_bit (1, 1)
45#define _GLIBCXX_GUARD_WAITING_BIT __guard_test_bit (2, 1)
46 __extension__ typedef int __guard __attribute__((mode (__DI__)));
47
48 // __cxa_vec_ctor has void return type.
49 typedef void __cxa_vec_ctor_return_type;
50#define _GLIBCXX_CXA_VEC_CTOR_RETURN(x) return
51 // Constructors and destructors do not return a value.
52 typedef void __cxa_cdtor_return_type;
53
54#ifdef __cplusplus
55 }
56} // namespace __cxxabiv1
57#endif
58
59#endif