diff --git a/Include/pyhash.h b/Include/pyhash.h
index dbcc974..2f39858 100644
--- a/Include/pyhash.h
+++ b/Include/pyhash.h
@@ -8,7 +8,7 @@
 /* Helpers for hash functions */
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(Py_hash_t) _Py_HashDouble(double);
-PyAPI_FUNC(Py_hash_t) _Py_HashPointer(void*);
+PyAPI_FUNC(Py_hash_t) _Py_HashPointer(const void*);
 PyAPI_FUNC(Py_hash_t) _Py_HashBytes(const void*, Py_ssize_t);
 #endif
 
diff --git a/Python/pyhash.c b/Python/pyhash.c
index 4c0b929..d381dc0 100644
--- a/Python/pyhash.c
+++ b/Python/pyhash.c
@@ -129,7 +129,7 @@
 }
 
 Py_hash_t
-_Py_HashPointer(void *p)
+_Py_HashPointer(const void *p)
 {
     Py_hash_t x;
     size_t y = (size_t)p;