diff --git a/src/H5PartPrivate.h b/src/H5PartPrivate.h
index 08b7cfe..d98ad3d 100644
--- a/src/H5PartPrivate.h
+++ b/src/H5PartPrivate.h
@@ -42,7 +42,7 @@ _H5Part_iteration_operator (
 
 void
 _H5Part_set_funcname (
-	char * const fname
+	const char * const fname
 	);
 
 const char *