On 07/05/19 11:05 +0200, Christophe Lyon wrote:
On Sat, 4 May 2019 at 16:36, Jonathan Wakely <jwak...@redhat.com> wrote:On 03/05/19 23:42 +0100, Jonathan Wakely wrote: >On 23/03/17 17:49 +0000, Jonathan Wakely wrote: >>On 12/03/17 13:16 +0100, Daniel Krügler wrote: >>>The following is an *untested* patch suggestion, please verify. >>> >>>Notes: My interpretation is that hash<error_condition> should be >>>defined outside of the _GLIBCXX_COMPATIBILITY_CXX0X block, please >>>double-check that course of action. >> >>That's right. >> >>>I noticed that the preexisting hash<error_code> did directly refer to >>>the private members of error_code albeit those have public access >>>functions. For consistency I mimicked that existing style when >>>implementing hash<error_condition>. >> >>I see no reason for that, so I've removed the friend declaration and >>used the public member functions. > >I'm going to do the same for hash<error_code> too. It can also use the >public members instead of being a friend. > > >>Although this is a DR, I'm treating it as a new C++17 feature, so I've >>adjusted the patch to only add the new specialization for C++17 mode. >>We're too close to the GCC 7 release to be adding new things to the >>default mode, even minor things like this. After GCC 7 is released we >>can revisit it and decide if we want to enable it for all modes. > >We never revisited that, and it's still only enabled for C++17 and up. >I guess that's OK, but we could enabled it for C++11 and 14 on trunk >if we want. Anybody care enough to argue for that? > >>Here's what I've tested and will be committing. >> >> > >>commit 90ca0fd91f5c65af370beb20af06bdca257aaf63 >>Author: Jonathan Wakely <jwak...@redhat.com> >>Date: Thu Mar 23 11:47:39 2017 +0000 >> >> Implement LWG 2686, std::hash<error_condition>, for C++17 >> 2017-03-23 Daniel Kruegler <daniel.krueg...@gmail.com> >> Implement LWG 2686, Why is std::hash specialized for error_code, >> but not error_condition? >> * include/std/system_error (hash<error_condition>): Define for C++17. >> * testsuite/20_util/hash/operators/size_t.cc (hash<error_condition>): >> Instantiate test for error_condition. >> * testsuite/20_util/hash/requirements/explicit_instantiation.cc >> (hash<error_condition>): Instantiate hash<error_condition>. >> >>diff --git a/libstdc++-v3/include/std/system_error b/libstdc++-v3/include/std/system_error >>index 6775a6e..ec7d25f 100644 >>--- a/libstdc++-v3/include/std/system_error >>+++ b/libstdc++-v3/include/std/system_error >>@@ -373,14 +373,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION >>_GLIBCXX_END_NAMESPACE_VERSION >>} // namespace >> >>-#ifndef _GLIBCXX_COMPATIBILITY_CXX0X >>- >>#include <bits/functional_hash.h> >> >>namespace std _GLIBCXX_VISIBILITY(default) >>{ >>_GLIBCXX_BEGIN_NAMESPACE_VERSION >> >>+#ifndef _GLIBCXX_COMPATIBILITY_CXX0X >> // DR 1182. >> /// std::hash specialization for error_code. >> template<> >>@@ -394,12 +393,27 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION >> return std::_Hash_impl::__hash_combine(__e._M_cat, __tmp); >> } >> }; >>+#endif // _GLIBCXX_COMPATIBILITY_CXX0X >>+ >>+#if __cplusplus > 201402L >>+ // DR 2686. >>+ /// std::hash specialization for error_condition. >>+ template<> >>+ struct hash<error_condition> >>+ : public __hash_base<size_t, error_condition> >>+ { >>+ size_t >>+ operator()(const error_condition& __e) const noexcept >>+ { >>+ const size_t __tmp = std::_Hash_impl::hash(__e.value()); >>+ return std::_Hash_impl::__hash_combine(__e.category(), __tmp); > >When I changed this from using __e._M_cat (as in Daniel's patch) to >__e.category() I introduced a bug, because the former is a pointer to >the error_category (and error_category objects are unique and so can >be identified by their address) and the latter is the object itself, >so we hash the bytes of an abstract base class instead of hashing the >pointer to it. Oops. > >Patch coming up to fix that. Here's the fix. Tested powerpc64le-linux, committed to trunk. I'll backport this to 7, 8 and 9 as well.Hi Jonathan, Does the new test lack dg-require-filesystem-ts ?
It lacks it, because it doesn't use the filesystem library at all.
I'm seeing link failures on arm-eabi (using newlib): Excess errors: /libstdc++-v3/src/c++17/fs_ops.cc:806: undefined reference to `chdir' /libstdc++-v3/src/c++17/fs_ops.cc:583: undefined reference to `mkdir' /libstdc++-v3/src/c++17/fs_ops.cc:1134: undefined reference to `chmod' /libstdc++-v3/src/c++17/../filesystem/ops-common.h:439: undefined reference to `chmod' /libstdc++-v3/src/c++17/fs_ops.cc:750: undefined reference to `pathconf' /libstdc++-v3/src/c++17/fs_ops.cc:769: undefined reference to `getcwd' Christophe
