1 /* MPFR internal header related to Static Assertions 2 3 Copyright 2012-2023 Free Software Foundation, Inc. 4 Contributed by the AriC and Caramba projects, INRIA. 5 6 This file is part of the GNU MPFR Library. 7 8 The GNU MPFR Library is free software; you can redistribute it and/or modify 9 it under the terms of the GNU Lesser General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or (at your 11 option) any later version. 12 13 The GNU MPFR Library is distributed in the hope that it will be useful, but 14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 16 License for more details. 17 18 You should have received a copy of the GNU Lesser General Public License 19 along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see 20 https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., 21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ 22 23 #ifndef __MPFR_STATIC_ASSERT_H__ 24 #define __MPFR_STATIC_ASSERT_H__ 25 26 #include "mpfr-cvers.h" /* for __MPFR_GNUC */ 27 28 /* How to use: 29 =========== 30 MPFR_STAT_STATIC_ASSERT: 31 + to check a condition at compile time within the statement section. 32 33 Note: In case one would need a static assertion in an expression, 34 a sizeof(...) instead of a typedef could be used. For instance, 35 see https://stackoverflow.com/questions/9229601/what-is-in-c-code 36 (about BUILD_BUG_ON_ZERO in the Linux kernel). 37 */ 38 39 #ifdef MPFR_USE_STATIC_ASSERT 40 41 /* C11 version */ 42 # if defined (__STDC_VERSION__) 43 # if (__STDC_VERSION__ >= 201112L) 44 # define MPFR_STAT_STATIC_ASSERT(c) _Static_assert((c), #c ) 45 # endif 46 # endif 47 48 /* Default version which should be compatible with nearly all compilers */ 49 # if !defined(MPFR_STAT_STATIC_ASSERT) 50 # if __MPFR_GNUC(4,8) 51 /* Get rid of annoying warnings "typedef '...' locally defined but not used" 52 (new in GCC 4.8). Thanks to Jonathan Wakely for this solution: 53 https://gcc.gnu.org/legacy-ml/gcc-help/2013-07/msg00142.html */ 54 # define MPFR_TYPEDEF_UNUSED __attribute__ ((unused)) 55 # else 56 # define MPFR_TYPEDEF_UNUSED 57 # endif 58 # define MPFR_ASSERT_CAT(a,b) MPFR_ASSERT_CAT_(a,b) 59 # define MPFR_ASSERT_CAT_(a,b) a ## b 60 # define MPFR_STAT_STATIC_ASSERT(c) do { \ 61 typedef enum { MPFR_ASSERT_CAT(MPFR_STATIC_ASSERT_CONST_,__LINE__) = !(c) } \ 62 MPFR_ASSERT_CAT(MPFR_ASSERT_,__LINE__)[!!(c) ? 1 : -1] \ 63 MPFR_TYPEDEF_UNUSED; } while (0) 64 # endif 65 66 #else 67 68 /* No support: default to classic assertions */ 69 # define MPFR_STAT_STATIC_ASSERT(c) MPFR_ASSERTN(c) 70 71 #endif 72 73 #endif 74