* ext/dl/cptr.c (rb_dlptr_to_str, rb_dlptr_to_s) adding documentation

* test/dl/test_cptr.rb (test_to_str, test_to_s) testing the
  stringification of DL::Ptr

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25677 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/dl/cptr.c

@@ -188,7 +188,12 @@ rb_dlptr_s_malloc(int argc, VALUE argv[], VALUE klass)
     return obj;
 }
 
-VALUE
+/*
+ * call-seq: to_i
+ *
+ * Returns the integer memory location of this DL::CPtr.
+ */
+static VALUE
 rb_dlptr_to_i(VALUE self)
 {
     struct ptr_data *data;
@@ -202,7 +207,7 @@ rb_dlptr_to_i(VALUE self)
  *
  * Cast this CPtr to a ruby object.
  */
-VALUE
+static VALUE
 rb_dlptr_to_value(VALUE self)
 {
     struct ptr_data *data;
@@ -285,7 +290,17 @@ rb_dlptr_free_get(VALUE self)
     return rb_dlcfunc_new(pdata->free, DLTYPE_VOID, "free<anonymous>", CFUNC_CDECL);
 }
 
-VALUE
+/*
+ * call-seq:
+ *
+ *    ptr.to_s        => string
+ *    ptr.to_s(len)   => string
+ *
+ * Returns the pointer contents as a string.  When called with no arguments,
+ * this method will return the contents until the first NULL byte.  When
+ * called with +len+, a string of +len+ bytes will be returned.
+ */
+static VALUE
 rb_dlptr_to_s(int argc, VALUE argv[], VALUE self)
 {
     struct ptr_data *data;
@@ -308,7 +323,17 @@ rb_dlptr_to_s(int argc, VALUE argv[], VALUE self)
     return val;
 }
 
-VALUE
+/*
+ * call-seq:
+ *
+ *    ptr.to_str        => string
+ *    ptr.to_str(len)   => string
+ *
+ * Returns the pointer contents as a string.  When called with no arguments,
+ * this method will return the contents with the length of this pointer's
+ * +size+. When called with +len+, a string of +len+ bytes will be returned.
+ */
+static VALUE
 rb_dlptr_to_str(int argc, VALUE argv[], VALUE self)
 {
     struct ptr_data *data;

test/dl/test_cptr.rb

@@ -3,6 +3,28 @@ require_relative '../ruby/envutil'
 
 module DL
   class TestCPtr < TestBase
+    def test_to_str
+      str = "hello world"
+      ptr = CPtr[str]
+
+      assert_equal 3, ptr.to_str(3).length
+      assert_equal str, ptr.to_str
+
+      ptr[5] = 0
+      assert_equal "hello\0world", ptr.to_str
+    end
+
+    def test_to_s
+      str = "hello world"
+      ptr = CPtr[str]
+
+      assert_equal 3, ptr.to_s(3).length
+      assert_equal str, ptr.to_s
+
+      ptr[5] = 0
+      assert_equal 'hello', ptr.to_s
+    end
+
     def test_minus
       str = "hello world"
       ptr = CPtr[str]