diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.c
index cb07694aea..1f38d00171 100644
--- a/src/backend/access/transam/xlogrecovery.c
+++ b/src/backend/access/transam/xlogrecovery.c
@@ -4861,7 +4861,7 @@ check_recovery_target_timeline(char **newval, void **extra, GucSource source)
 		rttg = RECOVERY_TARGET_TIMELINE_NUMERIC;
 
 		errno = 0;
-		strtoul(*newval, NULL, 0);
+		(void) strtoul(*newval, NULL, 0);
 		if (errno == EINVAL || errno == ERANGE)
 		{
 			GUC_check_errdetail("recovery_target_timeline is not a valid number.");