From b300fdeef440a3f11bb54f9f5a6ad85fd577cc2c Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Fri, 21 Sep 2018 20:45:44 +0300
Subject: [PATCH] Use CP_UTF8 when BOOST_SYSTEM_USE_UTF8 is defined

---
 .../system/detail/system_category_win32.hpp   | 26 ++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/include/boost/system/detail/system_category_win32.hpp b/include/boost/system/detail/system_category_win32.hpp
index 4739b89..72b3b3b 100644
--- a/include/boost/system/detail/system_category_win32.hpp
+++ b/include/boost/system/detail/system_category_win32.hpp
@@ -95,7 +95,17 @@ inline char const * system_category_message_win32( int ev, char * buffer, std::s
         return unknown_message_win32( ev, buffer, len );
     }
 
-    int r = boost::winapi::WideCharToMultiByte( CP_ACP_, 0, wbuffer, -1, buffer, static_cast<int>( len ), NULL, NULL );
+#if defined(BOOST_SYSTEM_USE_UTF8)
+
+    UINT_ code_page = CP_UTF8_;
+
+#else
+
+    UINT_ code_page = CP_ACP_;
+
+#endif
+
+    int r = boost::winapi::WideCharToMultiByte( code_page, 0, wbuffer, -1, buffer, static_cast<int>( len ), NULL, NULL );
 
     if( r == 0 )
     {
@@ -156,7 +166,17 @@ inline std::string system_category_message_win32( int ev )
 
     local_free lf_ = { lpMsgBuf };
 
-    int r = boost::winapi::WideCharToMultiByte( CP_ACP_, 0, lpMsgBuf, -1, 0, 0, NULL, NULL );
+#if defined(BOOST_SYSTEM_USE_UTF8)
+
+    UINT_ code_page = CP_UTF8_;
+
+#else
+
+    UINT_ code_page = CP_ACP_;
+
+#endif
+
+    int r = boost::winapi::WideCharToMultiByte( code_page, 0, lpMsgBuf, -1, 0, 0, NULL, NULL );
 
     if( r == 0 )
     {
@@ -165,7 +185,7 @@ inline std::string system_category_message_win32( int ev )
 
     std::string buffer( r, char() );
 
-    r = boost::winapi::WideCharToMultiByte( CP_ACP_, 0, lpMsgBuf, -1, &buffer[0], r, NULL, NULL );
+    r = boost::winapi::WideCharToMultiByte( code_page, 0, lpMsgBuf, -1, &buffer[0], r, NULL, NULL );
 
     if( r == 0 )
     {