diff --git a/judge/runguard.c b/judge/runguard.c
index a1097b8b7b..e1dc83f14d 100644
--- a/judge/runguard.c
+++ b/judge/runguard.c
@@ -799,7 +799,7 @@ void setrestrictions()
 	setlim(STACK);
 
 	if ( filesize!=RLIM_INFINITY ) {
-		verbose("setting filesize limit to %d bytes",(int)filesize);
+		verbose("setting filesize limit to %lu bytes",filesize);
 		lim.rlim_cur = lim.rlim_max = filesize;
 		setlim(FSIZE);
 	}