diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index 384399d..7637deb 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -889,7 +889,7 @@
 static PyObject *
 PyZlib_adler32(PyObject *self, PyObject *args)
 {
-    uLong adler32val = adler32(0L, Z_NULL, 0);
+    uLong adler32val = 1;  /* adler32(0L, Z_NULL, 0) */
     Byte *buf;
     int len, signed_val;
 
@@ -912,7 +912,7 @@
 static PyObject *
 PyZlib_crc32(PyObject *self, PyObject *args)
 {
-    uLong crc32val = crc32(0L, Z_NULL, 0);
+    uLong crc32val = 0;  /* crc32(0L, Z_NULL, 0) */
     Byte *buf;
     int len, signed_val;