2 * Portability macros used in include files.
4 * The canonical version of this file is maintained in the rra-c-util package,
5 * which can be found at <https://www.eyrie.org/~eagle/software/rra-c-util/>.
7 * Written by Russ Allbery <eagle@eyrie.org>
8 * Copyright 2015 Russ Allbery <eagle@eyrie.org>
9 * Copyright 2008, 2011-2012
10 * The Board of Trustees of the Leland Stanford Junior University
12 * Copying and distribution of this file, with or without modification, are
13 * permitted in any medium without royalty provided the copyright notice and
14 * this notice are preserved. This file is offered as-is, without any
17 * SPDX-License-Identifier: FSFAP
20 #ifndef PORTABLE_MACROS_H
21 #define PORTABLE_MACROS_H 1
24 * __attribute__ is available in gcc 2.5 and later, but only with gcc 2.7
25 * could you use the __format__ form of the attributes, which is what we use
26 * (to avoid confusion with other macros).
29 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
30 # define __attribute__(spec) /* empty */
35 * We use __alloc_size__, but it was only available in fairly recent versions
36 * of GCC. Suppress warnings about the unknown attribute if GCC is too old.
37 * We know that we're GCC at this point, so we can use the GCC variadic macro
38 * extension, which will still work with versions of GCC too old to have C99
39 * variadic macro support.
41 #if !defined(__attribute__) && !defined(__alloc_size__)
42 # if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 3)) \
43 && !defined(__clang__)
44 # define __alloc_size__(spec, args...) /* empty */
49 * LLVM and Clang pretend to be GCC but don't support all of the __attribute__
50 * settings that GCC does. For them, suppress warnings about unknown
51 * attributes on declarations. This unfortunately will affect the entire
52 * compilation context, but there's no push and pop available.
54 #if !defined(__attribute__) && (defined(__llvm__) || defined(__clang__))
55 # pragma GCC diagnostic ignored "-Wattributes"
59 * BEGIN_DECLS is used at the beginning of declarations so that C++
60 * compilers don't mangle their names. END_DECLS is used at the end.
65 # define BEGIN_DECLS extern "C" {
68 # define BEGIN_DECLS /* empty */
69 # define END_DECLS /* empty */
72 #endif /* !PORTABLE_MACROS_H */