Re: [PATCH] Define std::__invoke_r for INVOKE

[Jonathan Wakely]

On 17/05/19 10:15 +0100, Jonathan Wakely wrote:

I'm testing the attached fix. Thanks for the report.

Tests passed, patch committed to trunk.

commit 6ae6283255f58ad44a159970dce6f431cf46f293
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Fri May 17 10:10:10 2019 +0100

   Fix __invoke_r<void> to be valid in C++11

* include/bits/invoke.h [__cplusplus < 201703L] (__invoke_r<void>):

           Use _GLIBCXX14_CONSTEXPR because void functions cannot be constexpr
           in C++11.

diff --git a/libstdc++-v3/include/bits/invoke.h 
b/libstdc++-v3/include/bits/invoke.h
index 59e22da84d4..b2e9eee1a48 100644
--- a/libstdc++-v3/include/bits/invoke.h
+++ b/libstdc++-v3/include/bits/invoke.h
@@ -144,7 +144,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION

  // INVOKE<R> when R is cv void
  template<typename _Res, typename _Callable, typename... _Args>
-    constexpr __can_invoke_as_void<_Res, _Callable, _Args...>
+    _GLIBCXX14_CONSTEXPR __can_invoke_as_void<_Res, _Callable, _Args...>
    __invoke_r(_Callable&& __fn, _Args&&... __args)
    {
      using __result = __invoke_result<_Callable, _Args...>;