diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 703df790c28..5c0877b2797 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -1778,7 +1778,7 @@ plperl_inline_handler(PG_FUNCTION_ARGS)
 	/* Set up a callback for error reporting */
 	pl_error_context.callback = plperl_inline_callback;
 	pl_error_context.previous = error_context_stack;
-	pl_error_context.arg = (Datum) 0;
+	pl_error_context.arg = NULL;
 	error_context_stack = &pl_error_context;
 
 	/*