diff --git a/foreign/c/pointer.scm b/foreign/c/pointer.scm
index 29f9f23..b411479 100644
--- a/foreign/c/pointer.scm
+++ b/foreign/c/pointer.scm
@@ -102,7 +102,7 @@
   (kawa #t) ; FIXME
   (chibi #t)
   (gauche (define c-null? pointer-null?))
-  (mosh (define c-null? pointer-null?))
+  (mosh (define c-null? (lambda (pointer) (= (pointer->integer pointer) 0))))
   (else (define c-null?
           (lambda (pointer)
             (if (c-bytevector? pointer)