Documenting Windows Build Minimum Requirements (#937)

* testing that cxx standard less than 17 and filesystem off breaks build

* Turning filesystem on, but keeping cxx standard below 17

* Using CXX standard 17 and turning filesystem on, but also setting blt standard to 17

* adding a cmake check and breaking the build to see if the check works

* turning back on filesystem

* making sure the cmake error checks for c++17 or greater

* Update CMakeLists.txt

Co-authored-by: David Beckingsale <[email protected]>

---------

Co-authored-by: David Beckingsale <[email protected]>

Author: kab163

.github/workflows/build.yml

@@ -60,9 +60,9 @@ jobs:
             UMPIRE_ENABLE_TOOLS=Off
             UMPIRE_ENABLE_DEVELOPER_BENCHMARKS=On
             UMPIRE_ENABLE_BENCHMARKS=Off
-            BLT_CXX_STD=""
+            BLT_CXX_STD="c++17"
             CMAKE_CXX_STANDARD=17
             CMAKE_BUILD_TYPE=Release
             ${{ matrix.shared.args }}
           run-build: true
-          build-args: '--parallel 16'
+          build-args: '--parallel 16'

CMakeLists.txt

@@ -134,6 +134,16 @@ include(cmake/SetupCMakeBasics.cmake)
 include(cmake/SetupCompilerFlags.cmake)
 include(cmake/SetupUmpireThirdParty.cmake)
 
+if (WIN32)
+  if ((NOT UMPIRE_ENABLE_FILESYSTEM) OR (CMAKE_CXX_STANDARD LESS 17))
+    message(FATAL_ERROR "\
+    Windows builds require the FileSystem to be enabled \
+    and the C/C++ standard to be set to 17 or higher. \
+    Please re-configure with UMPIRE_ENABLE_FILESYSTEM=ON, \
+    with BLT_CXX_STD=c++17 or greater.")
+  endif()
+endif()
+
 add_subdirectory(src)
 
 configure_package_config_file(