diff --git a/api/sixtyfps-cpp/CMakeLists.txt b/api/sixtyfps-cpp/CMakeLists.txt
index 6fbb8cb29..61eae4327 100644
--- a/api/sixtyfps-cpp/CMakeLists.txt
+++ b/api/sixtyfps-cpp/CMakeLists.txt
@@ -24,6 +24,13 @@ add_library(SixtyFPS INTERFACE)
 add_library(SixtyFPS::SixtyFPS ALIAS SixtyFPS)
 target_link_libraries(SixtyFPS INTERFACE sixtyfps-cpp)
 target_compile_features(SixtyFPS INTERFACE cxx_std_17)
+if (CMAKE_SIZEOF_VOID_P EQUAL 8)
+    target_compile_definitions(SixtyFPS INTERFACE SIXTYFPS_TARGET_64)
+elseif (CMAKE_SIZEOF_VOID_P EQUAL 4)
+    target_compile_definitions(SixtyFPS INTERFACE SIXTYFPS_TARGET_32)
+else()
+    message(FATAL_ERROR "Unsupported CPU target architecture where the pointer size is neiter 4 nor 8")
+endif()
 
 file(GLOB api_headers RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}/include/"
     "${CMAKE_CURRENT_SOURCE_DIR}/include/*.h")
diff --git a/xtask/src/cbindgen.rs b/xtask/src/cbindgen.rs
index a932d290f..caae25d30 100644
--- a/xtask/src/cbindgen.rs
+++ b/xtask/src/cbindgen.rs
@@ -33,6 +33,13 @@ fn default_config() -> cbindgen::Config {
             .collect(),
             ..Default::default()
         },
+        defines: [
+            ("target_pointer_width = 64".into(), "SIXTYFPS_TARGET_64".into()),
+            ("target_pointer_width = 32".into(), "SIXTYFPS_TARGET_32".into()),
+        ]
+        .iter()
+        .cloned()
+        .collect(),
         ..Default::default()
     }
 }