Fix #33: Use _MSVC_LANG to determine the actual C++ standard version of Microsoft compilers.

.github/workflows/ci.yml

@@ -40,12 +40,19 @@ jobs:
           CXXFLAGS: -std=${{ matrix.std }}
         run: ./configure && make && make check
   msvc:
-    name: MSVC on windows-latest
+    name: Windows ${{ matrix.config }} build (C++${{ matrix.standard }})
     runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        config: [Debug, Release]
+        standard: [11, 17]
     steps:
       - uses: actions/checkout@v2
-      - name: Build and run tests
-        run: |
-          cmake -S . -B .
-          cmake --build .
-          ctest -C Debug
+      - name: Configure CMake
+        run: cmake -B build -D CMAKE_CXX_STANDARD=${{ matrix.standard }}
+      - name: Build
+        run: cmake --build build --config ${{ matrix.config }}
+      - name: Run tests
+        working-directory: build
+        run: ctest -C ${{ matrix.config }}

src/fsm.h

@@ -34,13 +34,13 @@
 
 namespace fsmlite {
     namespace detail {
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L || _MSVC_LANG >= 201703L
         template<class F, class... Args>
         using invoke_result_t = std::invoke_result_t<F, Args...>;
 
         template <class F, class... Args>
         using is_invocable = std::is_invocable<F, Args...>;
-#elif __cplusplus >= 201103L
+#elif __cplusplus >= 201103L || _MSVC_LANG >= 201103L
         template<class F, class... Args>
         using invoke_result_t = typename std::result_of<F&&(Args&&...)>::type;
 
@@ -357,7 +357,7 @@ namespace fsmlite {
             }
         };
 
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L || _MSVC_LANG >= 201703L
         /**
          * Generic transition class template (requires C++17).
          *

tests/CMakeLists.txt

@@ -1,12 +1,6 @@
 macro(fsmlite_add_test TESTNAME)
     add_executable(${TESTNAME} ${CMAKE_CURRENT_SOURCE_DIR}/${TESTNAME}.cpp)
     target_link_libraries(${TESTNAME} PRIVATE fsmlite)
-    if (MSVC AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.14)
-        target_compile_options(${TESTNAME}
-            PRIVATE
-                /Zc:__cplusplus
-        )
-    endif()
     add_test(NAME ${PROJECT_NAME}_${TESTNAME} COMMAND ${TESTNAME})
 endmacro(fsmlite_add_test)
 

tests/test_player.cpp

@@ -4,7 +4,7 @@
 #include <iostream>
 #include <string>
 
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L || _MSVC_LANG >= 201703L
 
 class player: public fsmlite::fsm<player> {
     friend class fsmlite::fsm<player>;  // base class needs access to transition_table

tests/test_row.cpp

@@ -2,7 +2,7 @@
 
 #include "fsm.h"
 
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L || _MSVC_LANG >= 201703L
 
 int value = 0;
 
@@ -55,7 +55,7 @@ private:
 
 int main()
 {
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L || _MSVC_LANG >= 201703L
     state_machine m;
     assert(m.current_state() == state_machine::Init);
     assert(value == 0);