From 154002bb5d6a161bb9a9a76030349fcec8ec40fe Mon Sep 17 00:00:00 2001
From: Howard Hinnant <hhinnant@apple.com>
Date: Thu, 31 Mar 2011 16:39:39 +0000
Subject: [PATCH] Provide a more readable error message for <atomic> until it
 is implemented.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@128636 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/atomic | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/atomic b/include/atomic
index daf64b265..31385a23d 100644
--- a/include/atomic
+++ b/include/atomic
@@ -530,6 +530,10 @@ void atomic_signal_fence(memory_order m);
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
+#if !__has_feature(cxx_atomic)
+#error <atomic> is not implemented
+#else
+
 typedef enum memory_order
 {
     memory_order_relaxed, memory_order_consume, memory_order_acquire,
@@ -1502,6 +1506,8 @@ typedef atomic<uintmax_t> atomic_uintmax_t;
 #define ATOMIC_LONG_LOCK_FREE 0
 #define ATOMIC_LLONG_LOCK_FREE 0
 
+#endif  //  !__has_feature(cxx_atomic)
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_ATOMIC