bits/long-double.h

   1 /* Properties of long double type.
   2    Copyright (C) 2016-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License  published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This header is included by <sys/cdefs.h>.
  20
  21    If long double is ABI-compatible with double, it should define
  22    __NO_LONG_DOUBLE_MATH to 1; otherwise, it should leave
  23    __NO_LONG_DOUBLE_MATH undefined.
  24
  25    If this build of the GNU C Library supports both long double
  26    ABI-compatible with double and some other long double format not
  27    ABI-compatible with double, it should define
  28    __LONG_DOUBLE_MATH_OPTIONAL to 1; otherwise, it should leave
  29    __LONG_DOUBLE_MATH_OPTIONAL undefined.
  30
  31    If __NO_LONG_DOUBLE_MATH is already defined, this header must not
  32    define anything; this is needed to work with the definition of
  33    __NO_LONG_DOUBLE_MATH in nldbl-compat.h.  */
  34
  35 /* In the default version of this header, long double is
  36    ABI-compatible with double.  */
  37 #ifndef __NO_LONG_DOUBLE_MATH
  38 # define __NO_LONG_DOUBLE_MATH  1
  39 #endif
  40
  41 /* The macro __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI is used to determine the
  42    choice of the underlying ABI of long double.  It will always assume
  43    a constant value for each translation unit.
  44
  45    If the value is non-zero, any API which is parameterized by the long
  46    double type (i.e the scanf/printf family of functions or the explicitly
  47    parameterized math.h functions) will be redirected to a compatible
  48    implementation using _Float128 ABI via symbols suffixed with ieee128.
  49
  50    The mechanism this macro uses to acquire may be a function
  51    of architecture, or target specific options used to invoke the
  52    compiler.  */
  53 #define __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 0