public inbox for libstdc++-cvs@sourceware.org help / color / mirror / Atom feed
From: Jonathan Wakely <redi@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r13-6328] libstdc++: Constrain net::executor constructors Date: Fri, 24 Feb 2023 14:26:29 +0000 (GMT) [thread overview] Message-ID: <20230224142629.B4DA138515E4@sourceware.org> (raw) https://gcc.gnu.org/g:8520132bc362d5f915eb1cb20038492e37b3cf88 commit r13-6328-g8520132bc362d5f915eb1cb20038492e37b3cf88 Author: Jonathan Wakely <jwakely@redhat.com> Date: Fri Feb 24 13:03:49 2023 +0000 libstdc++: Constrain net::executor constructors The TS says the arguments to these constructors shall meet the Executor requirements, so it's undefined if they don't. Constraining on a subset of those requirements won't affect valid cases, but prevents the majority of invalid cases from trying to instantiate the constructor. This prevents the non-explicit executor(Executor) constructor being a candidate anywhere that a net::executor could be constructed e.g. comparing ip::tcp::v4() == ip::udp::v4() would try to convert both operands to executor using that constructor, then compare then using operator==(const executor&, const executor&). libstdc++-v3/ChangeLog: * include/experimental/executor (executor): Constrain template constructors. Diff: --- libstdc++-v3/include/experimental/executor | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/include/experimental/executor b/libstdc++-v3/include/experimental/executor index cd75d99ddb3..1dae8925916 100644 --- a/libstdc++-v3/include/experimental/executor +++ b/libstdc++-v3/include/experimental/executor @@ -1012,6 +1012,9 @@ inline namespace v1 class executor { + template<typename _Executor> + using _Context_t = decltype(std::declval<_Executor&>().context()); + public: // construct / copy / destroy: @@ -1021,12 +1024,14 @@ inline namespace v1 executor(const executor&) noexcept = default; executor(executor&&) noexcept = default; - template<typename _Executor> + template<typename _Executor, + typename = _Require<is_lvalue_reference<_Context_t<_Executor>>>> executor(_Executor __e) : _M_target(make_shared<_Tgt1<_Executor>>(std::move(__e))) { } - template<typename _Executor, typename _ProtoAlloc> + template<typename _Executor, typename _ProtoAlloc, + typename = _Require<is_lvalue_reference<_Context_t<_Executor>>>> executor(allocator_arg_t, const _ProtoAlloc& __a, _Executor __e) : _M_target(allocate_shared<_Tgt2<_Executor, _ProtoAlloc>>(__a, std::move(__e), __a))
reply other threads:[~2023-02-24 14:26 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20230224142629.B4DA138515E4@sourceware.org \ --to=redi@gcc.gnu.org \ --cc=gcc-cvs@gcc.gnu.org \ --cc=libstdc++-cvs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).