diff --git a/CMakeLists.txt b/CMakeLists.txt
index 50d6e31..1a237b9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,6 +11,13 @@ file(GLOB HEADERS poly2tri/*.h poly2tri/common/*.h poly2tri/sweep/*.h)
 add_library(poly2tri ${SOURCES} ${HEADERS})
 target_include_directories(poly2tri INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
 
+get_target_property(poly2tri_target_type poly2tri TYPE)
+if(poly2tri_target_type STREQUAL SHARED_LIBRARY)
+  target_compile_definitions(poly2tri PRIVATE P2T_SHARED_EXPORTS)
+else()
+  target_compile_definitions(poly2tri PUBLIC P2T_STATIC_EXPORTS)
+endif()
+
 if(P2T_BUILD_TESTS)
     enable_testing()
     add_subdirectory(unittest)