[GitHub] [logging-log4cxx] rm5248 commented on a diff in pull request #148: Reduce std::ostream logging overhead

[GitBox <gi...@apache.org>]

rm5248 commented on code in PR #148:
URL: https://github.com/apache/logging-log4cxx/pull/148#discussion_r1015347242


##########
src/main/cpp/messagebuffer.cpp:
##########
@@ -149,10 +118,14 @@ CharMessageBuffer& CharMessageBuffer::operator<<(const char msg)
 
 CharMessageBuffer::operator std::basic_ostream<char>& ()
 {
-	if (m_priv->stream == 0)
+	if (!m_priv->stream)
 	{
+#if LOG4CXX_HAS_THREAD_LOCAL
+		thread_local static std::basic_ostringstream<char> sStream;
+		m_priv->stream = &sStream;
+#else
 		m_priv->stream = new std::basic_ostringstream<char>();
-
+#endif

Review Comment:
   At this point I'm not aware of any compiler that supports C++11 but not `thread_local`, would it make sense to simply make `m_priv->stream` a `thread_local` variable instead of holding a pointer?  I could be wrong here, but it looks like if two threads are logging at the same time they could both get the same `ostringstream`, thus defeating the purpose of the `thread_local`. 



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