PHP Resources

Definition and Usage

In PHP, Resource  is a special data type that refers to any external resource. A resource variable acts as a reference to external source of data such as stream, file, database etc. PHP uses relevent functions to create these resources. For example, fopen() function opens a disk file and its reference is stored in a resource variable.

PHP's Zend engine uses reference conting system. As a result, a resource with zero reference count is destroyed automatically by garbage collector. Hence, memory used by resource data type need not be freed manually.

Various types of resources can be handled in a PHP script, with the help of coresponding functions. Following table shows a select list −

In this context, PHP has get_resource_type() function that returns resource type of a variable.

Syntax

To declare an object of a class we need to use new statement

get_resource_type ( resource $handle ) : string

where $handle is the resource variable whose type is to be obtained. This function returns a string corresponding to resource type

Following example shows resource type of a disk file

Example

 Live Demo

<?php
$fp=fopen("test.txt","w");
var_dump($fp);
?>

Output

This will produce following result −

resource(5) of type (stream)

Following example uses get_resource_type() function

Example

 Live Demo

<?php
$fp = fopen("test.txt", "w");
echo get_resource_type($fp) . "
";
?>

Output

This will produce following result −

stream