diff --git a/src/private.h b/src/private.h
index 049749d3..21f24535 100644
--- a/src/private.h
+++ b/src/private.h
@@ -9,7 +9,7 @@
 #include <string>
 
 extern sgx_ql_logging_function_t logger_function;
-extern sgx_ql_logging_function_t logger_callback;
+extern sgx_ql_logging_callback_t logger_callback;
 
 ///////////////////////////////////////////////////////////////////////////////
 // Various internal functions which are not exported.