select: Fix "warning: no previous prototype for function".
[gnulib.git] / lib / isnand-nolibm.h
blobb3003c6ea3b0d8a481f2ec5eccf6b15da19acae7
1 /* Test for NaN that does not need libm.
2 Copyright (C) 2007-2020 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17 #if HAVE_ISNAND_IN_LIBC
18 /* Get declaration of isnan macro. */
19 # include <math.h>
20 # if (__GNUC__ >= 4) || (__clang_major__ >= 4)
21 /* GCC >= 4.0 and clang provide a type-generic built-in for isnan. */
22 # undef isnand
23 # define isnand(x) __builtin_isnan ((double)(x))
24 # else
25 # undef isnand
26 # define isnand(x) isnan ((double)(x))
27 # endif
28 #else
29 /* Test whether X is a NaN. */
30 # undef isnand
31 # define isnand rpl_isnand
32 extern int isnand (double x);
33 #endif