From 8520132bc362d5f915eb1cb20038492e37b3cf88 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 24 Feb 2023 13:03:49 +0000 Subject: [PATCH] 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. --- 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 cd75d99..1dae8925 100644 --- a/libstdc++-v3/include/experimental/executor +++ b/libstdc++-v3/include/experimental/executor @@ -1012,6 +1012,9 @@ inline namespace v1 class executor { + template + 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 + template>>> executor(_Executor __e) : _M_target(make_shared<_Tgt1<_Executor>>(std::move(__e))) { } - template + template>>> executor(allocator_arg_t, const _ProtoAlloc& __a, _Executor __e) : _M_target(allocate_shared<_Tgt2<_Executor, _ProtoAlloc>>(__a, std::move(__e), __a)) -- 2.7.4