Merge topic 'csharp_support_compiler_detection'

5c6c0344 C# support: add compiler detection for MSVC

diff --git a/Modules/CMakeCSharpCompiler.cmake.in b/Modules/CMakeCSharpCompiler.cmake.in
new file mode 100644
index 0000000..5ecc480
--- /dev/null
+++ b/Modules/CMakeCSharpCompiler.cmake.in
@@ -0,0 +1,9 @@
+set(CMAKE_CSharp_COMPILER "@CMAKE_CSharp_COMPILER@")
+set(CMAKE_CSharp_COMPILER_ID "@CMAKE_CSharp_COMPILER_ID@")
+set(CMAKE_CSharp_COMPILER_VERSION "@CMAKE_CSharp_COMPILER_VERSION@")
+
+set(CMAKE_CSharp_COMPILER_WORKS "@CMAKE_CSharp_COMPILER_WORKS@")
+
+set(CMAKE_CSharp_COMPILER_ID_RUN "@CMAKE_CSharp_COMPILER_ID_RUN@")
+set(CMAKE_CSharp_IGNORE_EXTENSIONS "inl;h;hpp;HPP;H;o;O;obj;OBJ;def;DEF;rc;RC")
+set(CMAKE_CSharp_SOURCE_FILE_EXTENSIONS "cs")
diff --git a/Modules/CMakeCSharpCompilerId.cs.in b/Modules/CMakeCSharpCompilerId.cs.in
new file mode 100644
index 0000000..987f63a
--- /dev/null
+++ b/Modules/CMakeCSharpCompilerId.cs.in
@@ -0,0 +1,63 @@
+using System;
+
+namespace CSharp
+{
+    public class CSharpApp
+    {
+        const string InfoCompiler = "INFO:compiler[Microsoft "
+#if PlatformToolsetv100
+        + "Visual Studio"
+#elif PlatformToolsetv110
+        + "Visual Studio"
+#elif PlatformToolsetv120
+        + "Visual Studio"
+#elif PlatformToolsetv140
+        + "Visual Studio"
+#elif PlatformToolsetv141
+        + "Visual Studio"
+#else
+        + "unknown"
+#endif
+        + "]";
+
+        const string InfoPlatform = "INFO:platform[Windows]";
+
+        const string InfoArchitecture = "INFO:arch["
+#if Platformx64
+        + "x64"
+#elif Platformx86
+        + "x86"
+#elif PlatformxWin32
+        + "Win32]"
+#else
+        + "unknown"
+#endif
+        + "]";
+
+        const string InfoCompilerVersion = "INFO:compiler_version["
+#if PlatformToolsetv100
+        + "2010"
+#elif PlatformToolsetv110
+        + "2012"
+#elif PlatformToolsetv120
+        + "2013"
+#elif PlatformToolsetv140
+        + "2015"
+#elif PlatformToolsetv141
+        + "2017"
+#else
+        + "9999"
+#endif
+        + "]";
+
+        static void Main(string[] args)
+        {
+            // we have to print the lines to make sure
+            // the compiler does not optimize them away ...
+            System.Console.WriteLine(InfoCompiler);
+            System.Console.WriteLine(InfoPlatform);
+            System.Console.WriteLine(InfoArchitecture);
+            System.Console.WriteLine(InfoCompilerVersion);
+        }
+    }
+}
diff --git a/Modules/CMakeCSharpInformation.cmake b/Modules/CMakeCSharpInformation.cmake
new file mode 100644
index 0000000..dc775bd
--- /dev/null
+++ b/Modules/CMakeCSharpInformation.cmake
@@ -0,0 +1,119 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+# This file sets the basic flags for the C# language in CMake.
+# It also loads the available platform file for the system-compiler
+# if it exists.
+
+set(CMAKE_BASE_NAME)
+get_filename_component(CMAKE_BASE_NAME "${CMAKE_CSharp_COMPILER}" NAME_WE)
+
+set(CMAKE_BUILD_TYPE_INIT Debug)
+
+set(CMAKE_CSharp_FLAGS_INIT "/define:TRACE /langversion:3 /nowin32manifest")
+set(CMAKE_CSharp_FLAGS_DEBUG_INIT "/debug:full /optimize- /warn:3 /errorreport:prompt /define:DEBUG")
+set(CMAKE_CSharp_FLAGS_RELEASE_INIT "/debug:none /optimize  /warn:1  /errorreport:queue")
+set(CMAKE_CSharp_FLAGS_RELWITHDEBINFO_INIT "/debug:full /optimize-")
+set(CMAKE_CSharp_FLAGS_MINSIZEREL_INIT "/debug:none /optimize")
+set(CMAKE_CSharp_LINKER_SUPPORTS_PDB ON)
+
+set(CMAKE_CSharp_STANDARD_LIBRARIES_INIT "System")
+
+if(CMAKE_SIZEOF_VOID_P EQUAL 4)
+  set(CMAKE_CSharp_FLAGS_INIT "/platform:x86 ${CMAKE_CSharp_FLAGS_INIT}")
+else()
+  set(CMAKE_CSharp_FLAGS_INIT "/platform:x64 ${CMAKE_CSharp_FLAGS_INIT}")
+endif()
+
+# This should be included before the _INIT variables are
+# used to initialize the cache.  Since the rule variables
+# have if blocks on them, users can still define them here.
+# But, it should still be after the platform file so changes can
+# be made to those values.
+
+# for most systems a module is the same as a shared library
+# so unless the variable CMAKE_MODULE_EXISTS is set just
+# copy the values from the LIBRARY variables
+if(NOT CMAKE_MODULE_EXISTS)
+  set(CMAKE_SHARED_MODULE_CSharp_FLAGS ${CMAKE_SHARED_LIBRARY_CSharp_FLAGS})
+  set(CMAKE_SHARED_MODULE_CREATE_CSharp_FLAGS ${CMAKE_SHARED_LIBRARY_CREATE_CSharp_FLAGS})
+endif()
+
+# add the flags to the cache based
+# on the initial values computed in the platform/*.cmake files
+# use _INIT variables so that this only happens the first time
+# and you can set these flags in the cmake cache
+set(CMAKE_CSharp_FLAGS_INIT "$ENV{CSharpFLAGS} ${CMAKE_CSharp_FLAGS_INIT}")
+# avoid just having a space as the initial value for the cache
+if(CMAKE_CSharp_FLAGS_INIT STREQUAL " ")
+  set(CMAKE_CSharp_FLAGS_INIT)
+endif()
+set (CMAKE_CSharp_FLAGS "${CMAKE_CSharp_FLAGS_INIT}" CACHE STRING
+     "Flags used by the C# compiler during all build types.")
+
+if(NOT CMAKE_NOT_USING_CONFIG_FLAGS)
+  set (CMAKE_CSharp_FLAGS_DEBUG "${CMAKE_CSharp_FLAGS_DEBUG_INIT}" CACHE STRING
+     "Flags used by the C# compiler during debug builds.")
+  set (CMAKE_CSharp_FLAGS_MINSIZEREL "${CMAKE_CSharp_FLAGS_MINSIZEREL_INIT}" CACHE STRING
+     "Flags used by the C# compiler during release builds for minimum size.")
+  set (CMAKE_CSharp_FLAGS_RELEASE "${CMAKE_CSharp_FLAGS_RELEASE_INIT}" CACHE STRING
+     "Flags used by the C# compiler during release builds.")
+  set (CMAKE_CSharp_FLAGS_RELWITHDEBINFO "${CMAKE_CSharp_FLAGS_RELWITHDEBINFO_INIT}" CACHE STRING
+     "Flags used by the C# compiler during release builds with debug info.")
+endif()
+
+if(CMAKE_CSharp_STANDARD_LIBRARIES_INIT)
+  set(CMAKE_CSharp_STANDARD_LIBRARIES "${CMAKE_CSharp_STANDARD_LIBRARIES_INIT}"
+    CACHE STRING "Libraries linked by default with all C# applications.")
+  mark_as_advanced(CMAKE_CSharp_STANDARD_LIBRARIES)
+endif()
+
+# set missing flags (if they do not exist). This is needed in the
+# unlikely case that you have only C# and no C/C++ targets in your
+# project.
+if(NOT EXISTS CMAKE_SHARED_LINKER_FLAGS)
+    set(CMAKE_SHARED_LINKER_FLAGS "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_SHARED_LINKER_FLAGS_DEBUG)
+    set(CMAKE_SHARED_LINKER_FLAGS_DEBUG "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_SHARED_LINKER_FLAGS_RELEASE)
+    set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_SHARED_LINKER_FLAGS_MINSIZEREL)
+    set(CMAKE_SHARED_LINKER_FLAGS_MINSIZEREL "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO)
+    set(CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "" CACHE STRING "" FORCE)
+endif()
+
+if(NOT EXISTS CMAKE_EXE_LINKER_FLAGS)
+    set(CMAKE_EXE_LINKER_FLAGS "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_EXE_LINKER_FLAGS_DEBUG)
+    set(CMAKE_EXE_LINKER_FLAGS_DEBUG "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_EXE_LINKER_FLAGS_RELEASE)
+    set(CMAKE_EXE_LINKER_FLAGS_RELEASE "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_EXE_LINKER_FLAGS_MINSIZEREL)
+    set(CMAKE_EXE_LINKER_FLAGS_MINSIZEREL "" CACHE STRING "" FORCE)
+endif()
+if(NOT EXISTS CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO)
+    set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "" CACHE STRING "" FORCE)
+endif()
+
+set(CMAKE_CSharp_CREATE_SHARED_LIBRARY "CSharp_NO_CREATE_SHARED_LIBRARY")
+set(CMAKE_CSharp_CREATE_SHARED_MODULE "CSharp_NO_CREATE_SHARED_MODULE")
+set(CMAKE_CSharp_LINK_EXECUTABLE "CSharp_NO_LINK_EXECUTABLE")
+
+mark_as_advanced(
+    CMAKE_CSharp_FLAGS
+    CMAKE_CSharp_FLAGS_RELEASE
+    CMAKE_CSharp_FLAGS_RELWITHDEBINFO
+    CMAKE_CSharp_FLAGS_MINSIZEREL
+    CMAKE_CSharp_FLAGS_DEBUG
+    )
+
+set(CMAKE_CSharp_USE_RESPONSE_FILE_FOR_OBJECTS 1)
+set(CMAKE_CSharp_INFORMATION_LOADED 1)
diff --git a/Modules/CMakeCompilerIdDetection.cmake b/Modules/CMakeCompilerIdDetection.cmake
index 2881cb1..484e1f0 100644
--- a/Modules/CMakeCompilerIdDetection.cmake
+++ b/Modules/CMakeCompilerIdDetection.cmake
@@ -15,7 +15,7 @@
 
 function(compiler_id_detection outvar lang)
 
-  if (NOT lang STREQUAL Fortran)
+  if (NOT lang STREQUAL Fortran AND NOT lang STREQUAL CSharp)
     file(GLOB lang_files
       "${CMAKE_ROOT}/Modules/Compiler/*-DetermineCompiler.cmake")
     set(nonlang CXX)
diff --git a/Modules/CMakeDetermineCSharpCompiler.cmake b/Modules/CMakeDetermineCSharpCompiler.cmake
new file mode 100644
index 0000000..1b8dd02
--- /dev/null
+++ b/Modules/CMakeDetermineCSharpCompiler.cmake
@@ -0,0 +1,43 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+if(NOT ${CMAKE_GENERATOR} MATCHES "Visual Studio ([^789]|[789][0-9])")
+   message(FATAL_ERROR
+    "C# is currently only supported for Microsoft Visual Studio 2010 and later.")
+endif()
+
+include(${CMAKE_ROOT}/Modules/CMakeDetermineCompiler.cmake)
+#include(Platform/${CMAKE_SYSTEM_NAME}-Determine-CSharp OPTIONAL)
+#include(Platform/${CMAKE_SYSTEM_NAME}-CSharp OPTIONAL)
+if(NOT CMAKE_CSharp_COMPILER_NAMES)
+  set(CMAKE_CSharp_COMPILER_NAMES csc)
+endif()
+
+# Build a small source file to identify the compiler.
+if(NOT CMAKE_CSharp_COMPILER_ID_RUN)
+  set(CMAKE_CSharp_COMPILER_ID_RUN 1)
+
+  # Try to identify the compiler.
+  set(CMAKE_CSharp_COMPILER_ID_STRINGS_PARAMETERS ENCODING UTF-16LE)
+  set(CMAKE_CSharp_COMPILER_ID)
+  include(${CMAKE_ROOT}/Modules/CMakeDetermineCompilerId.cmake)
+  CMAKE_DETERMINE_COMPILER_ID(CSharp CSFLAGS CMakeCSharpCompilerId.cs)
+
+  execute_process(COMMAND "${CMAKE_CSharp_COMPILER}" "/help" OUTPUT_VARIABLE output)
+  string(REPLACE "\n" ";" output "${output}")
+  foreach(line ${output})
+    string(TOUPPER ${line} line)
+    string(REGEX REPLACE "^.*COMPILER.*VERSION[^\\.0-9]*([\\.0-9]+).*$" "\\1" version "${line}")
+    if(version AND NOT "x${line}" STREQUAL "x${version}")
+      set(CMAKE_CSharp_COMPILER_VERSION ${version})
+      break()
+    endif()
+  endforeach()
+  message(STATUS "The CSharp compiler version is ${CMAKE_CSharp_COMPILER_VERSION}")
+endif()
+
+# configure variables set in this file for fast reload later on
+configure_file(${CMAKE_ROOT}/Modules/CMakeCSharpCompiler.cmake.in
+  ${CMAKE_PLATFORM_INFO_DIR}/CMakeCSharpCompiler.cmake
+  @ONLY
+  )
diff --git a/Modules/CMakeDetermineCompilerId.cmake b/Modules/CMakeDetermineCompilerId.cmake
index c5a2bcb..eae139d 100644
--- a/Modules/CMakeDetermineCompilerId.cmake
+++ b/Modules/CMakeDetermineCompilerId.cmake
@@ -164,6 +164,10 @@
       set(v Intel)
       set(ext vfproj)
       set(id_cl ifort.exe)
+    elseif(lang STREQUAL CSharp)
+      set(v 10)
+      set(ext csproj)
+      set(id_cl csc.exe)
     elseif(NOT "${vs_version}" VERSION_LESS 10)
       set(v 10)
       set(ext vcxproj)
@@ -447,8 +451,12 @@
     set(SIMULATE_ID)
     set(SIMULATE_VERSION)
     file(STRINGS ${file}
-      CMAKE_${lang}_COMPILER_ID_STRINGS LIMIT_COUNT 38 REGEX "INFO:[A-Za-z0-9_]+\\[[^]]*\\]")
+      CMAKE_${lang}_COMPILER_ID_STRINGS LIMIT_COUNT 38
+      ${CMAKE_${lang}_COMPILER_ID_STRINGS_PARAMETERS}
+      REGEX "INFO:[A-Za-z0-9_]+\\[[^]]*\\]")
     set(COMPILER_ID_TWICE)
+    # In C# binaries, some strings are found more than once.
+    list(REMOVE_DUPLICATES CMAKE_${lang}_COMPILER_ID_STRINGS)
     foreach(info ${CMAKE_${lang}_COMPILER_ID_STRINGS})
       if("${info}" MATCHES "INFO:compiler\\[([^]\"]*)\\]")
         if(COMPILER_ID)
diff --git a/Modules/CMakeTestCSharpCompiler.cmake b/Modules/CMakeTestCSharpCompiler.cmake
new file mode 100644
index 0000000..21b7236
--- /dev/null
+++ b/Modules/CMakeTestCSharpCompiler.cmake
@@ -0,0 +1,68 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+if(CMAKE_CSharp_COMPILER_FORCED)
+  # The compiler configuration was forced by the user.
+  # Assume the user has configured all compiler information.
+  set(CMAKE_CSharp_COMPILER_WORKS TRUE)
+  return()
+endif()
+
+include(CMakeTestCompilerCommon)
+
+unset(CMAKE_CSharp_COMPILER_WORKS CACHE)
+
+set(test_compile_file "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/testCSharpCompiler.cs")
+
+# This file is used by EnableLanguage in cmGlobalGenerator to
+# determine that that selected C# compiler can actually compile
+# and link the most basic of programs. If not, a fatal error
+# is set and cmake stops processing commands and will not generate
+# any makefiles or projects.
+if(NOT CMAKE_CSharp_COMPILER_WORKS)
+  PrintTestCompilerStatus("C#" "${CMAKE_CSharp_COMPILER}")
+  file(WRITE "${test_compile_file}"
+    "namespace Test {"
+    "   public class CSharp {"
+    "       static void Main(string[] args) {}"
+    "   }"
+    "}"
+    )
+  try_compile(CMAKE_CSharp_COMPILER_WORKS ${CMAKE_BINARY_DIR} "${test_compile_file}"
+    OUTPUT_VARIABLE __CMAKE_CSharp_COMPILER_OUTPUT
+    )
+  # Move result from cache to normal variable.
+  set(CMAKE_CSharp_COMPILER_WORKS ${CMAKE_CSharp_COMPILER_WORKS})
+  unset(CMAKE_CSharp_COMPILER_WORKS CACHE)
+  if(NOT CMAKE_CSharp_COMPILER_WORKS)
+    message("forcing compiler works to true (will be removed once C# support is integrated)")
+    set(CMAKE_CSharp_COMPILER_WORKS 1)
+  endif()
+  set(CSharp_TEST_WAS_RUN 1)
+endif()
+
+if(NOT CMAKE_CSharp_COMPILER_WORKS)
+  PrintTestCompilerStatus("C#" "${CMAKE_CSharp_COMPILER} -- broken")
+  file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
+    "Determining if the C# compiler works failed with "
+    "the following output:\n${__CMAKE_CSharp_COMPILER_OUTPUT}\n\n")
+  message(FATAL_ERROR "The C# compiler \"${CMAKE_CSharp_COMPILER}\" "
+    "is not able to compile a simple test program.\nIt fails "
+    "with the following output:\n ${__CMAKE_CSharp_COMPILER_OUTPUT}\n\n"
+    "CMake will not be able to correctly generate this project.")
+else()
+  if(CSharp_TEST_WAS_RUN)
+    PrintTestCompilerStatus("C#" "${CMAKE_CSharp_COMPILER} -- works")
+    file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
+      "Determining if the C# compiler works passed with "
+      "the following output:\n${__CMAKE_CSharp_COMPILER_OUTPUT}\n\n")
+  endif()
+
+  # Re-configure to save learned information.
+  configure_file(
+    ${CMAKE_ROOT}/Modules/CMakeCSharpCompiler.cmake.in
+    ${CMAKE_PLATFORM_INFO_DIR}/CMakeCSharpCompiler.cmake
+    @ONLY
+    )
+  include(${CMAKE_PLATFORM_INFO_DIR}/CMakeCSharpCompiler.cmake)
+endif()
diff --git a/Modules/CompilerId/VS-10.csproj.in b/Modules/CompilerId/VS-10.csproj.in
new file mode 100644
index 0000000..833dca7
--- /dev/null
+++ b/Modules/CompilerId/VS-10.csproj.in
@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{CAE07175-D007-4FC3-BFE8-47B392814159}</ProjectGuid>
+    <RootNamespace>CompilerId@id_lang@</RootNamespace>
+    <Keyword>Win32Proj</Keyword>
+    @id_system@
+    @id_system_version@
+    @id_WindowsTargetPlatformVersion@
+    @id_WindowsSDKDesktopARMSupport@
+  </PropertyGroup>
+  <PropertyGroup>
+    @id_PreferredToolArchitecture@
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|@id_platform@'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    @id_toolset@
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <!-- ============================================================ -->
+  <!-- ==                set preprocessor definitions            == -->
+  <!-- ============================================================ -->
+  <PropertyGroup>
+    <DefineConstants></DefineConstants>
+    <UnknownValue>Unknown</UnknownValue>
+  </PropertyGroup>
+  <!-- Platform -->
+  <PropertyGroup Condition="'$(Platform)'!=''">
+    <DefineConstants>$(DefineConstants);Platform$(Platform)</DefineConstants>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Platform)'==''">
+    <DefineConstants>$(DefineConstants);Platform$(UnknownValue)</DefineConstants>
+  </PropertyGroup>
+  <!-- PlatformToolset -->
+  <PropertyGroup Condition="'$(PlatformToolset)'!=''">
+    <DefineConstants>$(DefineConstants);PlatformToolset$(PlatformToolset)</DefineConstants>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(PlatformToolset)'==''">
+    <DefineConstants>$(DefineConstants);PlatformToolset$(UnknownValue)</DefineConstants>
+  </PropertyGroup>
+  <!-- ============================================================ -->
+  <PropertyGroup>
+    <OutputPath Condition="'$(Configuration)|$(Platform)'=='Debug|@id_platform@'">.\</OutputPath>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="@id_src@" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <PropertyGroup>
+    <PostBuildEvent>cd /D &quot;$(MSBuildToolsPath)&quot;
+if not %errorlevel%==0 exit -1
+if not exist @id_cl@ exit -2
+%40echo CMAKE_@id_lang@_COMPILER=$(MSBuildToolsPath)\@id_cl@</PostBuildEvent>
+  </PropertyGroup>
+</Project>
diff --git a/Tests/CMakeOnly/CMakeLists.txt b/Tests/CMakeOnly/CMakeLists.txt
index 7586de6..c692cbd 100644
--- a/Tests/CMakeOnly/CMakeLists.txt
+++ b/Tests/CMakeOnly/CMakeLists.txt
@@ -26,6 +26,9 @@
 if(CMAKE_Fortran_COMPILER)
   add_CMakeOnly_test(CompilerIdFortran)
 endif()
+if(CMAKE_GENERATOR MATCHES "Visual Studio ([^789]|[789][0-9])")
+  add_CMakeOnly_test(CompilerIdCSharp)
+endif()
 
 add_CMakeOnly_test(AllFindModules)
 
diff --git a/Tests/CMakeOnly/CompilerIdCSharp/CMakeLists.txt b/Tests/CMakeOnly/CompilerIdCSharp/CMakeLists.txt
new file mode 100644
index 0000000..6c07037
--- /dev/null
+++ b/Tests/CMakeOnly/CompilerIdCSharp/CMakeLists.txt
@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.7.0)
+project(CompilerIdCSharp CSharp)
+
+foreach(v
+    CMAKE_CSharp_COMPILER
+    CMAKE_CSharp_COMPILER_ID
+    CMAKE_CSharp_COMPILER_VERSION
+    )
+  if(${v})
+    message(STATUS "${v}=[${${v}}]")
+  else()
+    message(SEND_ERROR "${v} not set!")
+  endif()
+endforeach()
+
+# Version numbers may only contain numbers and periods.
+if(NOT CMAKE_CSharp_COMPILER_VERSION MATCHES
+    "^([0-9]+)(\\.([0-9]+))?(\\.([0-9]+))?(\\.([0-9]+))?$"
+    )
+  message(SEND_ERROR "Compiler version is not numeric!")
+endif()