From 4ec1e54099ff5f3d4e6533b9849af03d9a82a171 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Mon, 11 Oct 2021 02:02:22 +0300
Subject: [PATCH] Enable error_code construction from enums specializing
 std::is_error_code_enum. Fixes #70.

---
 include/boost/system/detail/error_code.hpp |  8 +++--
 test/CMakeLists.txt                        |  2 ++
 test/Jamfile.v2                            |  2 ++
 test/std_interop_test11.cpp                | 42 ++++++++++++++++++++++
 4 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 test/std_interop_test11.cpp

diff --git a/include/boost/system/detail/error_code.hpp b/include/boost/system/detail/error_code.hpp
index 494167c..1f0ac5d 100644
--- a/include/boost/system/detail/error_code.hpp
+++ b/include/boost/system/detail/error_code.hpp
@@ -107,8 +107,12 @@ public:
     }
 
     template<class ErrorCodeEnum> BOOST_SYSTEM_CONSTEXPR error_code( ErrorCodeEnum e,
-        typename detail::enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type* = 0 ) BOOST_NOEXCEPT:
-        d1_(), lc_flags_( 0 )
+        typename detail::enable_if<
+            is_error_code_enum<ErrorCodeEnum>::value
+#if defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
+            || std::is_error_code_enum<ErrorCodeEnum>::value
+#endif
+        >::type* = 0 ) BOOST_NOEXCEPT: d1_(), lc_flags_( 0 )
     {
         *this = make_error_code( e );
     }
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 6f8e34c..758b560 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -110,6 +110,8 @@ boost_test(TYPE run SOURCES ec_location_test2.cpp)
 boost_test(TYPE run SOURCES ec_what_test.cpp)
 boost_test(TYPE run SOURCES system_error_test3.cpp)
 
+boost_test(TYPE run SOURCES std_interop_test11.cpp)
+
 # result
 
 set(BOOST_TEST_COMPILE_FEATURES cxx_std_11)
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 77ec80d..0a6bc3e 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -132,6 +132,8 @@ run ec_location_test2.cpp ;
 run ec_what_test.cpp ;
 run system_error_test3.cpp ;
 
+run std_interop_test11.cpp ;
+
 # result
 
 import ../../config/checks/config : requires ;
diff --git a/test/std_interop_test11.cpp b/test/std_interop_test11.cpp
new file mode 100644
index 0000000..144f1c1
--- /dev/null
+++ b/test/std_interop_test11.cpp
@@ -0,0 +1,42 @@
+// Copyright 2021 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/system/error_code.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/config/pragma_message.hpp>
+#include <boost/config.hpp>
+#include <cerrno>
+
+#if !defined(BOOST_SYSTEM_HAS_SYSTEM_ERROR)
+
+BOOST_PRAGMA_MESSAGE( "BOOST_SYSTEM_HAS_SYSTEM_ERROR not defined, test will be skipped" )
+int main() {}
+
+#else
+
+#include <system_error>
+
+int main()
+{
+    {
+        boost::system::error_code ec = std::io_errc::stream;
+
+        BOOST_TEST( ec == std::io_errc::stream );
+        BOOST_TEST_NOT( ec != std::io_errc::stream );
+
+        ec.clear();
+
+        BOOST_TEST_NOT( ec == std::io_errc::stream );
+        BOOST_TEST( ec != std::io_errc::stream );
+
+        ec = std::io_errc::stream;
+
+        BOOST_TEST( ec == std::io_errc::stream );
+        BOOST_TEST_NOT( ec != std::io_errc::stream );
+    }
+
+    return boost::report_errors();
+}
+
+#endif