From fc4486c2472b84384d4a31d2436a91bdb9b29792 Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne@apple.com>
Date: Tue, 20 Aug 2019 18:21:06 +0000
Subject: [libc++] Implement LWG 3199

Summary:
The resolution of LWG 3199 makes sure that input-streaming into an empty bitset
does not set the failbit on the input stream.

Reviewers: mclow.lists, EricWF

Subscribers: christof, jkorous, dexonsmith, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D65105

llvm-svn: 369422
---
 libcxx/include/istream | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'libcxx/include')

diff --git a/libcxx/include/istream b/libcxx/include/istream
index d6217bbb800..bfbe5f24728 100644
--- a/libcxx/include/istream
+++ b/libcxx/include/istream
@@ -1619,7 +1619,7 @@ operator>>(basic_istream<_CharT, _Traits>& __is, bitset<_Size>& __x)
                  __is.rdbuf()->sbumpc();
             }
             __x = bitset<_Size>(__str);
-            if (__c == 0)
+            if (_Size > 0 && __c == 0)
                __state |= ios_base::failbit;
 #ifndef _LIBCPP_NO_EXCEPTIONS
         }
-- 
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