diff --git a/lang/basic/lib/salloc.c b/lang/basic/lib/salloc.c
index f968fb4e1..3e13b7d7d 100644
--- a/lang/basic/lib/salloc.c
+++ b/lang/basic/lib/salloc.c
@@ -3,11 +3,11 @@
 extern char *malloc() ;
 
 char * salloc(length)
-int length;
+unsigned length;
 {
 	char *c, *s;
 	c= malloc(length);
-	if( c== (char *) -1) error(5);
+	if( !c ) error(5);
 	for(s=c;s<c+length;s++) *s = 0;
 	return(c);
 }