php magic constants

__FILE__, __DIR__, __FUNCTION__, __CLASS__, __METHOD__, __TRAIT__ and __NAMESPACE__


PHP Magic Contants : Here are eight magical constants in PHP that change depending on where they are used.Some of these magical constants may provide useful information both within object-oriented programs as well as within procedural programs.
The __FILE__ constant is the current filename, __LINE__ is the current line number, __FUNCTION__ is the current function name, __METHOD__ is the current method name (if any), and __CLASS__ is the current class name (if any). Starting with PHP 5.3.0, __DIR__ is the directory that__FILE__ is in and __NAMESPACE__ is the current name‐ space. Starting in PHP 5.4.0, __TRAIT__ is the current trait name (if any).
Their current value depends on the context in which they occur and they all case-insensitive.

Some of the php magic constants and their definitions

Magic constant __LINE__

Magic constantDefinition
__LINE__The current line number of the file. It depends on where you use __LINE__

PHP magic contant Example ⇓__LINE__

the following Example will output the current line number.


Depending on where you use to output  the constant.That current line number  will be returned.
For me it displays as follows:-
 The current line number is 2

Magic constants

Magic constantDefinition
__LINE__The current line number of the file you are working on.
__FILE__The full path and filename of the file.
__DIR__The directory of the file.The __DIR__ constant tells the program to look in the same directory as the executing code for the files being included.
__FUNCTION__returns the name of the fucntion
__CLASS__returns the name of the class
__METHOD__It returns the method name of a class, this is useful in Object-Oriented PHP. The retuned name is case-sensitive.
__TRAIT__This feature is added in PHP 5.4.0 and it returns the trait as it was declared.
__NAMESPACE__This feature is added in PHP 5.3. and it returns the name of the current namespace as it was declared.

Example ⇓ Magic Constants

We will demonstrate how to use Magic Constants in OOP PHP

Output of the above file is as follows:-
    File name is :/var/www/test/index.php
User Name is : Tetla and Password is : 34_@POL