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| author | Jonathan Wakely <jwakely@redhat.com> | 2019-01-11 14:54:49 +0000 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2019-01-11 14:54:49 +0000 |
| commit | 17a73b3c47f58155350af2e1ca359e915ffedcae (patch) | |
| tree | 68fa79c1bceee9879bc6d5e711f02b905564bb2f | |
| parent | d58cb9659f8edd691f2c3f5595b6ac258eec58b9 (diff) | |
| download | gcc-17a73b3c47f58155350af2e1ca359e915ffedcae.zip gcc-17a73b3c47f58155350af2e1ca359e915ffedcae.tar.gz gcc-17a73b3c47f58155350af2e1ca359e915ffedcae.tar.bz2 | |
PR libstdc++/88802 define std::hash<nullptr_t> for C++17
PR libstdc++/88802
* include/bits/functional_hash.h (hash<nullptr_t>): Define
specialization for C++17 (P0513R0, LWG 2817).
* testsuite/20_util/hash/nullptr.cc: New test.
From-SVN: r267845
| -rw-r--r-- | libstdc++-v3/ChangeLog | 5 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/functional_hash.h | 10 | ||||
| -rw-r--r-- | libstdc++-v3/testsuite/20_util/hash/nullptr.cc | 37 |
3 files changed, 52 insertions, 0 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 37bd9e2..4c2470c 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,5 +1,10 @@ 2019-01-11 Jonathan Wakely <jwakely@redhat.com> + PR libstdc++/88802 + * include/bits/functional_hash.h (hash<nullptr_t>): Define + specialization for C++17 (P0513R0, LWG 2817). + * testsuite/20_util/hash/nullptr.cc: New test. + PR libstdc++/88125 * config/abi/pre/gnu.ver (GLIBCXX_3.4.6): Remove unused duplicate pattern for std::basic_stringbuf::str(). diff --git a/libstdc++-v3/include/bits/functional_hash.h b/libstdc++-v3/include/bits/functional_hash.h index 2245fad..32dc00c 100644 --- a/libstdc++-v3/include/bits/functional_hash.h +++ b/libstdc++-v3/include/bits/functional_hash.h @@ -254,6 +254,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION operator()(long double __val) const noexcept; }; +#if __cplusplus >= 201703L + template<> + struct hash<nullptr_t> : public __hash_base<size_t, nullptr_t> + { + size_t + operator()(nullptr_t) const noexcept + { return 0; } + }; +#endif + // @} group hashes // Hint about performance of hash functor. If not fast the hash-based diff --git a/libstdc++-v3/testsuite/20_util/hash/nullptr.cc b/libstdc++-v3/testsuite/20_util/hash/nullptr.cc new file mode 100644 index 0000000..366db67 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/hash/nullptr.cc @@ -0,0 +1,37 @@ +// 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/>. + +// { dg-options "-std=gnu++17" } +// { dg-do run { target c++17 } } + +#include <functional> +#include <testsuite_hooks.h> + +void +test01() +{ + auto h1 = std::hash<std::nullptr_t>{}(nullptr); + static_assert(std::is_same_v<decltype(h1), std::size_t>); + auto h2 = std::hash<std::nullptr_t>{}(nullptr); + VERIFY( h1 == h2 ); +} + +int +main() +{ + test01(); +} |