From: Yedidya Feldblum <yfeldblum@fb.com>
Date: Fri, 3 Nov 2017 02:44:08 +0000 (-0700)
Subject: Alias std::launder when it is available
X-Git-Tag: v2017.11.06.00~8
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=61ba3c11be5e7831bdb659fc0c35979910c3f637;p=folly.git

Alias std::launder when it is available

Summary: [Folly] Alias `std::launder` when it is available.

Reviewed By: Orvid

Differential Revision: D6221443

fbshipit-source-id: 33136a8744a39db01fb05513d5ed5476ea67559a
---

diff --git a/folly/lang/Launder.h b/folly/lang/Launder.h
index fb0e5f7a..b54d7e68 100644
--- a/folly/lang/Launder.h
+++ b/folly/lang/Launder.h
@@ -16,9 +16,26 @@
 
 #pragma once
 
+#include <new>
+
 #include <folly/CPortability.h>
 #include <folly/Portability.h>
 
+/***
+ *  include or backport:
+ *  * std::launder
+ */
+
+#if __cpp_lib_launder >= 201606
+
+namespace folly {
+
+/* using override */ using std::launder;
+
+} // namespace folly
+
+#else
+
 namespace folly {
 
 /**
@@ -54,3 +71,5 @@ void launder(void const volatile*) = delete;
 template <typename T, typename... Args>
 void launder(T (*)(Args...)) = delete;
 } // namespace folly
+
+#endif