SciCompMod · reneSchm · Jul 11, 2026
diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
@@ -51,6 +51,15 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ffp-model=strict") # to avoid FP differences in CI
 endif()
 
+# support for Emscripten/WASM
+set(patch_random123_wasm)
+if(EMSCRIPTEN)
+    message(NOTICE "Detected Emscripten toolchain")
+    set(patch_random123_wasm git apply ${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/random123_wasm.patch)
+    set(CMAKE_TOOLCHAIN_FILE $ENV{EMSDK_HOME}/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake)
+    set(CMAKE_EXECUTABLE_SUFFIX ".html")
+endif()
+
 set(CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake" ${CMAKE_MODULE_PATH})
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
@@ -167,6 +176,7 @@ if(CMAKE_BUILD_TYPE STREQUAL "Release" OR CMAKE_BUILD_TYPE STREQUAL "RELEASE")
     elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
         string(APPEND MEMILIO_CXX_FLAGS_ENABLE_WARNING_ERRORS
             "-Wno-stringop-overread;"
+            "-Wno-c2y-extensions;" # use c2y extensions, as they have been supported for a long time
         )
     endif()
 endif()

diff --git a/cpp/thirdparty/CMakeLists.txt b/cpp/thirdparty/CMakeLists.txt
@@ -177,7 +177,9 @@ message(STATUS "Downloading Random123 library")
 include(FetchContent)
 FetchContent_Declare(Random123
     GIT_REPOSITORY https://github.com/DEShawResearch/random123
-    GIT_TAG ${MEMILIO_RANDOM123_VERSION})
+    GIT_TAG ${MEMILIO_RANDOM123_VERSION}
+    PATCH_COMMAND ${patch_random123_wasm}
+    UPDATE_DISCONNECTED 1)
 FetchContent_MakeAvailable(Random123)
 
 add_library(Random123 INTERFACE)

diff --git a/cpp/thirdparty/random123_wasm.patch b/cpp/thirdparty/random123_wasm.patch
@@ -0,0 +1,13 @@
+diff --git a/include/Random123/features/gccfeatures.h b/include/Random123/features/gccfeatures.h
+index 51c46aa..9315b8b 100644
+--- a/include/Random123/features/gccfeatures.h
++++ b/include/Random123/features/gccfeatures.h
+@@ -34,7 +34,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+ #define R123_GNUC_VERSION (__GNUC__*10000 + __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__)
+
+-#if !defined(__x86_64__) && !defined(__i386__) && !defined(__powerpc__) && !defined(__arm__) && !defined(__aarch64__) && !defined(__s390x__)
++#if !defined(__x86_64__) && !defined(__i386__) && !defined(__powerpc__) && !defined(__arm__) && !defined(__aarch64__) && !defined(__s390x__) && !defined(__wasm__)
+ #  error "This code has only been tested on x86, powerpc and a few arm platforms."
+ #include <including_a_nonexistent_file_will_stop_some_compilers_from_continuing_with_a_hopeless_task>
+ { /* maybe an unbalanced brace will terminate the compilation */
diff --git a/pycode/memilio-simulation/CMakeLists.txt b/pycode/memilio-simulation/CMakeLists.txt
@@ -14,8 +14,9 @@ endif()
 set(CMAKE_CXX_STANDARD "20")
 set(CMAKE_CXX_STANDARD_REQUIRED "20")
 
+option(MEMILIO_BUILD_SHARED_LIBS "Build memilio as a shared library." ON)
 option(MEMILIO_USE_BUNDLED_PYBIND11 "Use pybind11 bundled with this library." ON)
-mark_as_advanced(MEMILIO_USE_BUNDLED_PYBIND11)
+mark_as_advanced(MEMILIO_BUILD_SHARED_LIBS MEMILIO_USE_BUNDLED_PYBIND11)
 
 include(GNUInstallDirs) # set to gnu folders. No cache variable so this is not global
 

diff --git a/pycode/memilio-simulation/pyproject.toml b/pycode/memilio-simulation/pyproject.toml
@@ -47,7 +47,7 @@ build-backend = "scikit_build_core.build"
 
 [tool.scikit-build]
 cmake.version = ">=3.13"
-cmake.args = ["-DMEMILIO_BUILD_SHARED_LIBS:BOOL=ON"]
+cmake.args = []
 wheel.packages = ["memilio"]
 wheel.install-dir = "memilio/simulation"
 sdist.cmake = true