diff --git a/ext/dl/cptr.c b/ext/dl/cptr.c
index 0c85a91b6c..96f318be53 100644
--- a/ext/dl/cptr.c
+++ b/ext/dl/cptr.c
@@ -388,7 +388,7 @@ rb_dlptr_inspect(VALUE self)
     char str[1024];
 
     TypedData_Get_Struct(self, struct ptr_data, &dlptr_data_type, data);
-    snprintf(str, 1023, "#<%s:%p ptr=%p size=%ld free=%p>",
+    snprintf(str, 1023, "#<%s:%p ptr=%#lx size=%ld free=%#lx>",
 	     rb_class2name(CLASS_OF(self)), data, data->ptr, data->size, data->free);
     return rb_str_new2(str);
 }
diff --git a/test/dl/test_cptr.rb b/test/dl/test_cptr.rb
index 2b40a16fb1..5bc98ef35b 100644
--- a/test/dl/test_cptr.rb
+++ b/test/dl/test_cptr.rb
@@ -59,8 +59,8 @@ module DL
       ptr = CPtr.new(0)
       inspect = ptr.inspect
       assert_match(/size=#{ptr.size}/, inspect)
-      assert_match(/free=#{ptr.free}/, inspect)
-      assert_match(/ptr=#{ptr.to_i}/, inspect)
+      assert_match(/free=#{sprintf("%#x", ptr.free.to_i)}/, inspect)
+      assert_match(/ptr=#{sprintf("%#x", ptr.to_i)}/, inspect)
     end
 
     def test_to_ptr_string