diff --git a/src/tcp_rules.c b/src/tcp_rules.c
index 7eb5659..fc8b4ae 100644
--- a/src/tcp_rules.c
+++ b/src/tcp_rules.c
@@ -766,7 +766,7 @@
 		arg++;
 
 		curpx->conf.args.ctx = ARGC_CAP;
-		expr = sample_parse_expr(args, &arg, file, line, err, &curpx->conf.args);
+		expr = sample_parse_expr(args, &arg, file, line, err, &curpx->conf.args, NULL);
 		if (!expr) {
 			memprintf(err,
 			          "'%s %s %s' : %s",
@@ -847,7 +847,7 @@
 		}
 
 		curpx->conf.args.ctx = ARGC_TRK;
-		expr = sample_parse_expr(args, &arg, file, line, err, &curpx->conf.args);
+		expr = sample_parse_expr(args, &arg, file, line, err, &curpx->conf.args, NULL);
 		if (!expr) {
 			memprintf(err,
 			          "'%s %s %s' : %s",