[libcxx] Fix PR 22468 - std::function<void()> does not accept non-void-returning functions Summary: The bug can be found here: http://llvm.org/bugs/show_bug.cgi?id=22468 `__invoke_void_return_wrapper` is needed to properly handle calling a function that returns a value but where the std::function return type is void. Without this '-Wsystem-headers' will cause `function::operator()(...)` to not compile. Reviewers: eugenis, K-ballo, mclow.lists Reviewed By: mclow.lists Subscribers: cfe-commits Differential Revision: http://reviews.llvm.org/D7444 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@228705 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__functional_base b/include/__functional_base index 6766793..e174e0c 100644 --- a/include/__functional_base +++ b/include/__functional_base
@@ -419,6 +419,26 @@ typedef decltype(__invoke(_VSTD::declval<_Tp>(), _VSTD::declval<_Args>()...)) type; }; +template <class _Ret> +struct __invoke_void_return_wrapper +{ + template <class ..._Args> + static _Ret __call(_Args&&... __args) + { + return __invoke(_VSTD::forward<_Args>(__args)...); + } +}; + +template <> +struct __invoke_void_return_wrapper<void> +{ + template <class ..._Args> + static void __call(_Args&&... __args) + { + __invoke(_VSTD::forward<_Args>(__args)...); + } +}; + template <class _Tp> class _LIBCPP_TYPE_VIS_ONLY reference_wrapper : public __weak_result_type<_Tp> 