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PHP Magic Constants
Introduction to PHP Magic Constants
__LINE__
The __LINE__ magic constant returns the current line number of the file. It is useful for debugging purposes, allowing developers to track the execution flow within the script.
__FILE__
The __FILE__ magic constant returns the full path and filename of the file. This is particularly useful for including files relative to the current script's directory.
__DIR__
The __DIR__ magic constant returns the directory of the file. It is often used to include or require files in the same directory, ensuring portability across different environments.
__FUNCTION__
The __FUNCTION__ magic constant returns the name of the function where it is used. This can be helpful for logging or debugging function calls.
__CLASS__
The __CLASS__ magic constant returns the name of the class where it is used. It is beneficial for dynamic class handling and introspection.
__TRAIT__
The __TRAIT__ magic constant returns the name of the trait where it is used. This is useful when working with traits in PHP, providing context about the trait in use.
<?php
echo "This is line number " . __LINE__ . "\n";
echo "This file is located at " . __FILE__ . "\n";
echo "This directory is " . __DIR__ . "\n";
function testFunction() {
echo "This function is called " . __FUNCTION__ . "\n";
}
class TestClass {
function displayClassName() {
echo "This class is called " . __CLASS__ . "\n";
}
}
trait TestTrait {
function displayTraitName() {
echo "This trait is called " . __TRAIT__ . "\n";
}
}
testFunction();
$test = new TestClass();
$test->displayClassName();
class UseTrait {
use TestTrait;
}
$traitTest = new UseTrait();
$traitTest->displayTraitName();
?>
__METHOD__
The __METHOD__ magic constant returns the name of the class method where it is used. It is useful for logging and debugging method calls.
__NAMESPACE__
The __NAMESPACE__ magic constant returns the name of the current namespace. This is crucial for managing code organization and avoiding name conflicts in larger projects.
