[PATCH] Define C11 macros such as FLT_DECIMAL_DIG for C++17

[Jonathan Wakely]

On 13/06/19 17:09 +0100, Jonathan Wakely wrote:
>The C++17 library was rebased on C11 by https://wg21.link/p0063r3 so
>these nine macros are needed for C++17 conformance.
>
>gcc:
>
>	* ginclude/float.h (FLT_DECIMAL_DIG, DBL_DECIMAL_DIG, LDBL_DECIMAL_DIG)
>	(FLT_HAS_SUBNORM, DBL_HAS_SUBNORM, LDBL_HAS_SUBNORM, FLT_TRUE_MIN)
>	(DBL_TRUE_MIN, LDBL_TRUE_MIN): Also define for C++17.
>
>libstdc++-v3:
>
>	* testsuite/18_support/headers/cfloat/values_c++17.cc: New test.
>
>
>Tested x86_64-linux and powerpc64le-linux.
>
>OK for trunk and gcc-9-branch?

Ping.


>commit ce40ee46ca226c102c548032184345fe9f5d352e
>Author: Jonathan Wakely <jwakely@redhat.com>
>Date:   Thu Jun 13 11:38:33 2019 +0100
>
>    Define C11 macros such as FLT_DECIMAL_DIG for C++17
>
>    The C++17 library was rebased on C11 by https://wg21.link/p0063r3 so
>    these nine macros are needed for C++17 conformance.
>
>    gcc:
>
>            * ginclude/float.h (FLT_DECIMAL_DIG, DBL_DECIMAL_DIG, LDBL_DECIMAL_DIG)
>            (FLT_HAS_SUBNORM, DBL_HAS_SUBNORM, LDBL_HAS_SUBNORM, FLT_TRUE_MIN)
>            (DBL_TRUE_MIN, LDBL_TRUE_MIN): Also define for C++17.
>
>    libstdc++-v3:
>
>            * testsuite/18_support/headers/cfloat/values_c++17.cc: New test.
>
>diff --git a/gcc/ginclude/float.h b/gcc/ginclude/float.h
>index 9ebae057d34..4767d7b9dfb 100644
>--- a/gcc/ginclude/float.h
>+++ b/gcc/ginclude/float.h
>@@ -210,7 +210,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
>
> #endif /* C99 */
>
>-#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
>+#if (defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) \
>+     || (defined (__cplusplus) && __cplusplus >= 201703L)
> /* Versions of DECIMAL_DIG for each floating-point type.  */
> #undef FLT_DECIMAL_DIG
> #undef DBL_DECIMAL_DIG
>diff --git a/libstdc++-v3/testsuite/18_support/headers/cfloat/values_c++17.cc b/libstdc++-v3/testsuite/18_support/headers/cfloat/values_c++17.cc
>new file mode 100644
>index 00000000000..f3efd204d17
>--- /dev/null
>+++ b/libstdc++-v3/testsuite/18_support/headers/cfloat/values_c++17.cc
>@@ -0,0 +1,37 @@
>+// { dg-options "-std=gnu++17" }
>+// { dg-do compile { target c++17 } }
>+
>+// Copyright (C) 2019 Free Software Foundation, Inc.
>+//
>+// This file is part of the GNU ISO C++ Library.  This library 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, or (at your option)
>+// any later version.
>+
>+// This library 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 library; see the file COPYING3.  If not see
>+// <http://www.gnu.org/licenses/>.
>+
>+#include <cfloat>
>+#include "values.cc"
>+
>+namespace gnu17
>+{
>+  double d1 = DBL_DECIMAL_DIG;
>+  double d2 = DBL_HAS_SUBNORM;
>+  double d3 = DBL_TRUE_MIN;
>+
>+  float f1 = FLT_DECIMAL_DIG;
>+  float f2 = FLT_HAS_SUBNORM;
>+  float f3 = FLT_TRUE_MIN;
>+
>+  long double ld1 = LDBL_DECIMAL_DIG;
>+  long double ld2 = LDBL_HAS_SUBNORM;
>+  long double ld3 = LDBL_TRUE_MIN;
>+}