--- /sys/src/libdraw/string.c	Thu Nov  3 18:05:49 2005
+++ /sys/src/libdraw/string.c	Mon Mar 10 20:22:32 2014
@@ -78,7 +78,7 @@
 	}else
 		rptr = &r;
 	sf = nil;
-	while((*s || *r) && len){
+	while((*s || *r) && len > 0){
 		max = Max;
 		if(len < max)
 			max = len;