1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/* Macros for declaring functions as non-returning.
Copyright (C) 2017-2019 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert and Bruno Haible. */
#ifndef _NORETURN_H
#define _NORETURN_H 1
/* A "non-returning" function is a function which cannot return normally.
It can transfer control only through longjmp(), throw (in C++), or similar
mechanisms.
This file defines two macros _GL_NORETURN_FUNC and _GL_NORETURN_FUNCPTR,
that declare a function to be non-returning.
_GL_NORETURN_FUNC is for use in function declarations and function
definitions.
_GL_NORETURN_FUNCPTR is for use on function pointers.
Comparison of this file with <stdnoreturn.h>:
<stdnoreturn.h> defines a macro (or keyword) _Noreturn that declares
a function to be non-returning. _Noreturn is only for use in function
declarations and function definitions.
Therefore, if the non-returning functions you have to declare are unlikely
to be accessed through function pointers, and if the efficiency with C++
compilers other than g++, clang, MSVC++ is not an issue to you, you can use
module 'stdnoreturn' instead of this one, and _Noreturn instead of
_GL_NORETURN_FUNC.
*/
/* Declares that a function is nonreturning.
Use in C only code:
_GL_NORETURN_FUNC extern void func (void);
extern _GL_NORETURN_FUNC void func (void);
extern void _GL_NORETURN_FUNC func (void);
Use in C++ only code for a function with C linkage:
extern "C" { _GL_NORETURN_FUNC void func (void); }
Use in C++ only code for a function with C++ linkage:
_GL_NORETURN_FUNC extern void func (void);
Use in C & C++ code for a function with C linkage:
#ifdef __cplusplus
extern "C" {
#endif
_GL_NORETURN_FUNC void func (void);
#ifdef __cplusplus
}
#endif
Use in C & C++ code for a function with current language linkage:
_GL_NORETURN_FUNC extern void func (void);
*/
#if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__)) \
|| (0x5110 <= __SUNPRO_C)
/* For compatibility with _GL_NORETURN_FUNCPTR on clang, use
__attribute__((__noreturn__)), not _Noreturn. */
# define _GL_NORETURN_FUNC __attribute__ ((__noreturn__))
#elif 1200 <= _MSC_VER
/* Use MSVC specific syntax. */
# define _GL_NORETURN_FUNC __declspec (noreturn)
#elif defined __cplusplus
/* Use ISO C++11 syntax when the compiler supports it. */
# if (__cplusplus >= 201103 && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
|| (_MSC_VER >= 1900)
# define _GL_NORETURN_FUNC [[noreturn]]
# else
# define _GL_NORETURN_FUNC /* empty */
# endif
#else
/* Use ISO C11 syntax when the compiler supports it. */
# if __STDC_VERSION__ >= 201112 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
# define _GL_NORETURN_FUNC _Noreturn
# else
# define _GL_NORETURN_FUNC /* empty */
# endif
#endif
/* Declares that a function is nonreturning.
Use in types and declarations that involve function pointers:
_GL_NORETURN_FUNCPTR void (*funcptr) (void);
*/
#if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__)) \
|| (0x5110 <= __SUNPRO_C)
# define _GL_NORETURN_FUNCPTR __attribute__ ((__noreturn__))
#else
# define _GL_NORETURN_FUNCPTR /* empty */
#endif
/* Comments about the compiler dependent language features:
- '_Noreturn' - standardized by ISO C11, available in C only (not in C++),
and not applicable to pointers.
- '[[noreturn]]' - standardized by ISO C++11, available in C++ only,
and not applicable to pointers.
- '__attribute__((__noreturn__))' - available in GCC and clang only,
both in C and C++.
- '__declspec(noreturn)' - available in MSVC only,
both in C and C++, not applicable to pointers.
*/
#endif /* _NORETURN_H */
|
