* ext/dl/cptr.c (rb_dlptr_ptr, rb_dlptr_ref) adding documentation

* test/dl/test_cptr.rb (test_ref_ptr) testing CPtr#ref and CPtr#ptr

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25608 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/dl/cptr.c

@@ -210,6 +210,12 @@ rb_dlptr_to_value(VALUE self)
     return (VALUE)(data->ptr);
 }
 
+/*
+ * call-seq: ptr
+ *
+ * Returns a DL::CPtr that is a dereferenced pointer for this DL::CPtr.
+ * Analogous to the star operator in C.
+ */
 VALUE
 rb_dlptr_ptr(VALUE self)
 {
@@ -219,6 +225,12 @@ rb_dlptr_ptr(VALUE self)
     return rb_dlptr_new(*((void**)(data->ptr)),0,0);
 }
 
+/*
+ * call-seq: ref
+ *
+ * Returns a DL::CPtr that is a reference pointer for this DL::CPtr.
+ * Analogous to the ampersand operator in C.
+ */
 VALUE
 rb_dlptr_ref(VALUE self)
 {

test/dl/test_cptr.rb

@@ -3,6 +3,14 @@ require_relative '../ruby/envutil'
 
 module DL
   class TestCPtr < TestBase
+    def test_ref_ptr
+      ary = [0,1,2,4,5]
+      addr = CPtr.new(dlwrap(ary))
+      assert_equal addr.to_i, addr.ref.ptr.to_i
+
+      assert_equal addr.to_i, (+ (- addr)).to_i
+    end
+
     def test_to_value
       ary = [0,1,2,4,5]
       addr = CPtr.new(dlwrap(ary))