diff --git a/include/qpid/dispatch/internal/thread_annotations.h b/include/qpid/dispatch/internal/thread_annotations.h
index 826283769..5cb0fefb4 100644
--- a/include/qpid/dispatch/internal/thread_annotations.h
+++ b/include/qpid/dispatch/internal/thread_annotations.h
@@ -85,6 +85,6 @@
 #define TA_SCOPED_CAP                THREAD_ANNOTATION(scoped_lockable)
 #define TA_NO_THREAD_SAFETY_ANALYSIS THREAD_ANNOTATION(no_thread_safety_analysis)
 
-typedef void* core_thread_capability_t TA_CAP("core_thread");
+typedef void const *core_thread_capability_t TA_CAP("core_thread");
 
-extern core_thread_capability_t core_thread_capability;
+extern const core_thread_capability_t core_thread_capability;