Support shared library building on Windows

CMakeLists.txt

@@ -26,6 +26,14 @@ function(rerun_strict_warning_settings target)
         # TODO(andreas): Try to enable /Wall
         target_compile_options(${target} PRIVATE /W4)
 
+        if(BUILD_SHARED_LIBS)
+            # If we are building as shared libs, we are going to have to disable the C4251
+            # warning, as it would trigger for any datatype derived from a STL class
+            # See also https://github.com/protocolbuffers/protobuf/blob/v26.1/cmake/README.md#notes-on-compiler-warnings
+            # We need also to make it public, otherwise downstream code will be flooded by c4251 warnings
+            target_compile_options(${target} PUBLIC /wd4251)
+        endif()
+
         # CMAKE_COMPILE_WARNING_AS_ERROR is only directly supported starting in CMake `3.24`
         # https://cmake.org/cmake/help/latest/prop_tgt/COMPILE_WARNING_AS_ERROR.html
         if(CMAKE_COMPILE_WARNING_AS_ERROR)
@@ -144,8 +152,20 @@ FetchContent_Declare(LoguruGitRepo
     GIT_REPOSITORY "https://github.com/emilk/loguru" # can be a filesystem path
     GIT_TAG "master"
 )
+
+# Loguru does not support being build with BUILD_SHARED_LIBS=ON on Windows
+# so we always compile it with BUILD_SHARED_LIBS=OFF on Windows
+if(MSVC AND BUILD_SHARED_LIBS)
+    set(BUILD_SHARED_LIBS_RERUN_SDK ${BUILD_SHARED_LIBS})
+    set(BUILD_SHARED_LIBS OFF)
+endif()
+
 FetchContent_MakeAvailable(LoguruGitRepo) # defines target 'loguru::loguru'
 
+if(MSVC AND BUILD_SHARED_LIBS_RERUN_SDK)
+    set(BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS_RERUN_SDK})
+endif()
+
 # Set any loguru compile-time flags before calling MakeAvailable()
 # Stacktraces are not yet supported on Windows.
 if(NOT WIN32)

rerun_cpp/CMakeLists.txt

@@ -116,6 +116,29 @@
 
 target_link_libraries(rerun_sdk PRIVATE rerun_arrow_target)
 
+if(MSVC AND BUILD_SHARED_LIBS)
+    # This code is required by to support BUILD_SHARED_LIBS=ON on Windows
+    # Differently from Linux/macOS, by default Windows does not support
+    # exporting all symbols of a shared library, and instead requires
+    # annotating manually each class that needs to be exported
+    # The WINDOWS_EXPORT_ALL_SYMBOLS PROPERTY (set in the next line)
+    # simply the process of having shared library on Windows, by emulating
+    # in CMake the behaviour of Linux/macOS. However, it does not cover
+    # static variables.
+    set_property(TARGET rerun_sdk PROPERTY WINDOWS_EXPORT_ALL_SYMBOLS ON)
+    # For exporting static variables in shared libraries in Windows, it
+    # is not possible to just use WINDOWS_EXPORT_ALL_SYMBOLS, we need instead
+    # to manually annotate with the appropriate storage-class attributes
+    # all static variables. The easiest way to do so is use GenerateExportHeader
+    # module to generate a rerun_sdk_export.hpp header file that define the RERUN_SDK_EXPORT
+    # macro, and add that macro to all static variables. The RERUN_SDK_EXPORT is defined
+    # in src/rerun/rerun_sdk_export.hpp . The definition of the macro changes depending
+    # of whether the library is compiled as static or shared, so for shared builds we
+    # set the RERUN_SDK_COMPILED_AS_SHARED_LIBRARY to let the header know if the build
+    # is a shared library one
+    target_compile_definitions(rerun_sdk PUBLIC RERUN_SDK_COMPILED_AS_SHARED_LIBRARY)
+endif()
+
 # -----------------------------------------------------------------------------
 # Installation.
 set(RERUN_SDK_INSTALL_CMAKE_DIR "lib/cmake/rerun_sdk")
@@ -125,6 +148,7 @@
     EXPORT rerun_sdkTargets
     LIBRARY DESTINATION lib
     ARCHIVE DESTINATION lib
+    RUNTIME DESTINATION bin
     INCLUDES DESTINATION include
 )
 

rerun_cpp/src/rerun/archetypes/clear_ext.cpp

@@ -1,5 +1,10 @@
 #include "clear.hpp"
 
+// <CODEGEN_COPY_TO_HEADER>
+#include "../rerun_sdk_export.hpp"
+
+// </CODEGEN_COPY_TO_HEADER>
+
 // Uncomment for better auto-complete while editing the extension.
 // #define EDIT_EXTENSION
 
@@ -12,9 +17,9 @@ namespace rerun {
 
             // <CODEGEN_COPY_TO_HEADER>
 
-            static const Clear FLAT;
+            RERUN_SDK_EXPORT static const Clear FLAT;
 
-            static const Clear RECURSIVE;
+            RERUN_SDK_EXPORT static const Clear RECURSIVE;
 
             Clear(bool _is_recursive = false)
                 : Clear(components::ClearIsRecursive(_is_recursive)) {}

rerun_cpp/src/rerun/archetypes/transform3d_ext.cpp

@@ -1,5 +1,10 @@
 #include "transform3d.hpp"
 
+// <CODEGEN_COPY_TO_HEADER>
+#include "../rerun_sdk_export.hpp"
+
+// </CODEGEN_COPY_TO_HEADER>
+
 // Uncomment for better auto-complete while editing the extension.
 // #define EDIT_EXTENSION
 
@@ -12,7 +17,7 @@ namespace rerun {
         /// Identity transformation.
         ///
         /// Applying this transform does not alter an entity's transformation.
-        static const Transform3D IDENTITY;
+        RERUN_SDK_EXPORT static const Transform3D IDENTITY;
 
         /// New 3D transform from translation/matrix datatype.
         ///