diff --git a/librf/src/future.h b/librf/src/future.h
index 0f03a78..ee1f7d5 100644
--- a/librf/src/future.h
+++ b/librf/src/future.h
@@ -240,6 +240,12 @@ namespace resumef
 		{
 			return _state->cancellation_requested();
 		}
+/*
+		void unhandled_exception() 
+		{
+			std::terminate(); 
+		}
+*/
 
 		//return_value/return_void 只能由派生类去实现
 
diff --git a/librf/src/rf_task.h b/librf/src/rf_task.h
index b60ce3b..8b638e1 100644
--- a/librf/src/rf_task.h
+++ b/librf/src/rf_task.h
@@ -149,9 +149,9 @@ namespace resumef
 	//这个'函数对象'被调用后，返回generator<_Ty>/future_t<_Ty>类型
 	//然后'函数对象'作为异步执行的上下文状态保存起来
 	template<class _Ctx>
-	struct ctx_task_t : public task_t<typename std::result_of<_Ctx()>::type>
+	struct ctx_task_t : public task_t<typename std::decay<decltype(std::declval<_Ctx>()())>::type>
 	{
-		typedef task_t<typename std::result_of<_Ctx()>::type> base_type;
+		typedef task_t<typename std::decay<decltype(std::declval<_Ctx>()())>::type> base_type;
 		using base_type::_future;
 
 		typedef _Ctx context_type;
diff --git a/tutorial/test_async_dynamic_go.cpp b/tutorial/test_async_dynamic_go.cpp
index 8973110..2237f61 100644
--- a/tutorial/test_async_dynamic_go.cpp
+++ b/tutorial/test_async_dynamic_go.cpp
@@ -14,11 +14,11 @@ std::array<std::array<std::array<int32_t, M>, M>, 3> dynamic_cells;
 
 void test_dynamic_go()
 {
-	auto co_star = [](int j)
+	auto co_star = [](int j) -> resumef::future_t<int>
 	{
 		for (int i = 0; i < M; ++i)
 		{
-			go[=]()
+			go[=]() -> std::experimental::generator<int>
 			{
 				for (int k = 0; k < M; ++k)
 				{
diff --git a/tutorial/test_async_resumable.cpp b/tutorial/test_async_resumable.cpp
index 0df692d..2f1a995 100644
--- a/tutorial/test_async_resumable.cpp
+++ b/tutorial/test_async_resumable.cpp
@@ -26,7 +26,7 @@ void dump(size_t idx, std::string name, T start, T end, intptr_t count)
 static const intptr_t N = 3000000;
 //static const int N = 10;
 
-auto yield_switch(intptr_t coro)
+auto yield_switch(intptr_t coro) -> std::experimental::generator<intptr_t>
 {
 	for (intptr_t i = 0; i < N / coro; ++i)
 		co_yield i;
@@ -42,7 +42,7 @@ void resumable_switch(intptr_t coro, size_t idx)
 	for (intptr_t i = 0; i < coro; ++i)
 	{
 		//go yield_switch(coro);
-		go [=]
+		go [=] ()->std::experimental::generator<intptr_t>
 		{
 			for (intptr_t i = 0; i < N / coro; ++i)
 				co_yield i;
diff --git a/tutorial/test_async_yield_return.cpp b/tutorial/test_async_yield_return.cpp
index ba80993..ca0c3b4 100644
--- a/tutorial/test_async_yield_return.cpp
+++ b/tutorial/test_async_yield_return.cpp
@@ -10,7 +10,7 @@
 using namespace resumef;
 
 //std::experimental::generator<int>
-auto test_yield_int()
+auto test_yield_int() -> std::experimental::generator<int>
 {
 	std::cout << "1 will yield return" << std::endl;
 	co_yield 1;
@@ -43,7 +43,7 @@ auto test_yield_void()
 }
 */
 
-auto test_yield_void()
+auto test_yield_void() -> std::experimental::generator<std::nullptr_t>
 {
 	std::cout << "block 1 will yield return" << std::endl;
 	co_yield_void;
diff --git a/vs_proj/librf.cpp b/vs_proj/librf.cpp
index 4dd42c7..b9fe2cf 100644
--- a/vs_proj/librf.cpp
+++ b/vs_proj/librf.cpp
@@ -33,7 +33,7 @@ int main(int argc, const char* argv[])
 	else
 		resumable_main_benchmark_asio_server();
 */
-	return 0;
+	//return 0;
 
 	resumable_main_when_all();
 	resumable_main_multi_thread();
diff --git a/vs_proj/librf.vcxproj b/vs_proj/librf.vcxproj
index df42f62..d0a2884 100644
--- a/vs_proj/librf.vcxproj
+++ b/vs_proj/librf.vcxproj
@@ -23,7 +23,7 @@
     <ProjectGuid>{C1D4A6BD-592F-4E48-8178-7C87219BF80E}</ProjectGuid>
     <Keyword>Win32Proj</Keyword>
     <RootNamespace>librf</RootNamespace>
-    <WindowsTargetPlatformVersion>10.0</WindowsTargetPlatformVersion>
+    <WindowsTargetPlatformVersion>10.0.18362.0</WindowsTargetPlatformVersion>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
@@ -42,7 +42,7 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
-    <PlatformToolset>v142</PlatformToolset>
+    <PlatformToolset>v140</PlatformToolset>
     <CharacterSet>NotSet</CharacterSet>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
@@ -88,7 +88,7 @@
     <ClCompile>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;ASIO_STANDALONE;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;ASIO_STANDALONE;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;ASIO_DISABLE_CONCEPTS=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\librf;..\..\asio\asio\include;..\..\asio-1.10.6\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <AdditionalOptions>/await</AdditionalOptions>
@@ -104,7 +104,7 @@
     <ClCompile>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>_DEBUG;_CONSOLE;ASIO_STANDALONE;RESUMEF_DEBUG_COUNTER=0;RESUMEF_ENABLE_MULT_SCHEDULER=1;RESUMEF_USE_BOOST_ANY=0;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>_DEBUG;_CONSOLE;ASIO_STANDALONE;RESUMEF_DEBUG_COUNTER=0;RESUMEF_ENABLE_MULT_SCHEDULER=1;RESUMEF_USE_BOOST_ANY=0;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;ASIO_DISABLE_CONCEPTS=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\librf;..\..\asio\asio\include;..\..\asio-1.10.6\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <AdditionalOptions>/await</AdditionalOptions>
@@ -126,7 +126,7 @@
       <Optimization>Full</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;ASIO_STANDALONE;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;ASIO_STANDALONE;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;ASIO_DISABLE_CONCEPTS=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>
       </SDLCheck>
       <AdditionalIncludeDirectories>..\librf;..\..\asio\asio\include;..\..\asio-1.10.6\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
@@ -153,7 +153,7 @@
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>NDEBUG;_CONSOLE;ASIO_STANDALONE;RESUMEF_ENABLE_MULT_SCHEDULER=1;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>NDEBUG;_CONSOLE;ASIO_STANDALONE;RESUMEF_ENABLE_MULT_SCHEDULER=1;_SILENCE_CXX17_ALLOCATOR_VOID_DEPRECATION_WARNING=1;ASIO_DISABLE_CONCEPTS=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>..\librf;..\..\asio\asio\include;..\..\asio-1.10.6\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <AdditionalOptions>/await</AdditionalOptions>
       <ExceptionHandling>Sync</ExceptionHandling>