PHP magic Method

PHP treats all methods starting with _ (two underscores) in the class as magic methods. It is generally recommended that you do not add _ as the prefix before the custom method.

Magic method:

1.
_ Construct ()

The default constructor of the class. If _ construct () and a method with the same name as the class appear together, _ construct () is called by default instead of the same name method. Generally, the User-Defined constructor uses _ construct ().
2. _ destruct ()
Class destructor, which is executed when all references to the object are deleted or the object is explicitly destroyed.
3. _ Get ($ name)
It can be simply summarized as: If attribute a exists and is of the Public type when the $ object-> A method is used to read the attributes of an object, the value of this attribute is directly returned; if attribute a does not exist or is not directly accessible, the _ Get ($ name) method is called and the return value prevails. You can use this method to restrict external access to internal properties, or perform reflection operations similar to those in Java.
4. _ set ($ name, $ value)
And_ Get ($ name)Similarly, when you assign a value to an attribute in the format of $ object-> A = 17, if attribute a exists and is public, you can directly assign a value to attribute; if attribute a does not exist or is protected/private, the _ set ($ name, $ value) method is called.
5. _ call ($ name, $ arguments)/_ callstatic ($ name, $ arguments)
When a non-existent or inaccessible method is called, The _ call ($ name, $ arguments) method is called. When a non-existing or inaccessible method is called in a static method, the _ callstatic ($ name, $ arguments) method is called.
6. _ tostring ()
It is called directly when an object is printed. Such as Echo $ object;
7. _ clone ()
It is called directly when an object is copied. For example, $ A = new action (); $ A = $ object;
8. _ isset ($ name)/_ unset ($ name)
When isset () or empty () is used for non-existent or inaccessible attributes, __isset () is called. When unset is a non-existent or inaccessible attribute, __unset () will be called. Otherwise, this attribute can be directly unset.
9. _ set_state ()
When var_export () is used to output an object, __set_state () is called. The output content is subject to the return value of this magic method. Note: var_export () and var_dump () are similar, but the content output by var_export () conforms to the PHP syntax. Note:

$ Test = new test ();
$ B = var_export ($ test, true );
Var_dump ($ B );

Class test {

Public $;
Public static function _ set_state ($ array ){
$ AB = new test ();
$ AB-> A = 10;
Return $ AB;
}
}

10. _ autoload ($ name)
When instantiating an object, if the corresponding class does not exist, this method is called. Note: This method is a global function and the parameter is the name of the class.
11. _ sleep ()/_ wakup ()
.

Magic constant:
1. _ line __
Returns the current row number in the file.
2. _ file __
Returns the complete path of the file.
3. _ function __
The name of the function to be returned.
4. _ class __
The name of the class to be returned.
5. _ method __

Returns the name of the class method. Note that _ method _ returns the form of "Class: function", while _ function _ returns the form of "function.

From: http://www.cppblog.com/amazon/archive/2011/10/10/157950.html