diff --git a/include/sltdl/sltdl.h b/include/sltdl/sltdl.h
index 3039529..5d1b51b 100644
--- a/include/sltdl/sltdl.h
+++ b/include/sltdl/sltdl.h
@@ -39,6 +39,9 @@ typedef enum lt_dlpriority lt_dlloader_priority;
 
 /* binary-compatible type definitions */
 typedef void * lt_ptr;
+typedef void * lt_module;
+typedef void * lt_dlloader;
+typedef void * lt_user_data;
 
 struct lt_symdef {
 	const char *    name;