From 1d845408dd1bb50208bf20f03c0459f76c2444d3 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Thu, 25 Apr 2019 01:01:48 +0300
Subject: [PATCH] Fix thread safety issue in std interop

---
 include/boost/system/detail/config.hpp               | 5 +++++
 include/boost/system/detail/std_interoperability.hpp | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/include/boost/system/detail/config.hpp b/include/boost/system/detail/config.hpp
index 2ad8201..ab1f304 100644
--- a/include/boost/system/detail/config.hpp
+++ b/include/boost/system/detail/config.hpp
@@ -22,6 +22,11 @@
 # undef BOOST_SYSTEM_HAS_SYSTEM_ERROR
 #endif
 
+#if defined(BOOST_NO_CXX11_HDR_MUTEX)
+// Required for thread-safe map manipulation
+# undef BOOST_SYSTEM_HAS_SYSTEM_ERROR
+#endif
+
 // BOOST_SYSTEM_NOEXCEPT
 // Retained for backward compatibility
 
diff --git a/include/boost/system/detail/std_interoperability.hpp b/include/boost/system/detail/std_interoperability.hpp
index f52e99e..a6ec728 100644
--- a/include/boost/system/detail/std_interoperability.hpp
+++ b/include/boost/system/detail/std_interoperability.hpp
@@ -10,6 +10,7 @@
 #include <system_error>
 #include <map>
 #include <memory>
+#include <mutex>
 
 //
 
@@ -92,6 +93,9 @@ inline std::error_category const & to_std_category( boost::system::error_categor
         typedef std::map< boost::system::error_category const *, std::unique_ptr<std_category>, cat_ptr_less > map_type;
 
         static map_type map_;
+        static std::mutex map_mx_;
+
+        std::lock_guard<std::mutex> guard( map_mx_ );
 
         map_type::iterator i = map_.find( &cat );