Loader changes & optimizations related to issue #2551
diff --git a/user_guide_src/source/libraries/loader.rst b/user_guide_src/source/libraries/loader.rst
index 1597bf1..19446a9 100644
--- a/user_guide_src/source/libraries/loader.rst
+++ b/user_guide_src/source/libraries/loader.rst
@@ -261,6 +261,32 @@
This method is an alias of the :doc:`config file loading
method <config>`: ``$this->config->load()``
+$this->load->is_loaded('library_name')
+======================================
+
+The ``is_loaded()`` method allows you to check if a class has already
+been loaded or not.
+
+.. note:: The word "class" here refers to libraries and drivers.
+
+If the requested class has been loaded, the method returns its assigned
+name in the CI Super-object and FALSE if it's not::
+
+ $this->load->library('form_validation');
+ $this->load->is_loaded('Form_validation'); // returns 'form_validation'
+
+ $this->load->is_loaded('Nonexistent_library'); // returns FALSE
+
+.. important:: If you have more than one instance of a class (assigned to
+ different properties), then the first one will be returned.
+
+::
+
+ $this->load->library('form_validation', $config, 'fv');
+ $this->load->library('form_validation');
+
+ $this->load->is_loaded('Form_validation'); // returns 'fv'
+
Application "Packages"
======================