What is PHP is_resource() Function?
If you want to know whether a variable is a resource or not, use is_resource() function. Resources include file handle, database connection, network socket.
Syntax:
is_resource(variable)
Parameters:
The Function has 1 parameter which is required-
variable (Required): It specifies a variable.
Return Values:
The function returns-
- TRUE, if the variable is an active resource.
- FALSE, if the variable is an active resource.
Examples:
Example 1:
<?php
/* Suppose, the file.txt exists in the current directory. */
$handle = fopen("file.txt", "r");
if (is_resource($handle)) {
echo "The resource is a valid resource.<br />";
}
fclose($handle); // It closes the resource.
if (!is_resource($handle)) {
echo "The resource is now closed and no longer valid.";
}
?>
Output:
The resource is a valid resource.
The resource is now closed and no longer valid.
Practical usage of PHP is_resource() function:
- Before operating a file, you can use is_resource() function to make sure that the resource is valid and open.
- Before working with a database connection or network socket, you can use is_resource() function to make sure that the connection is valid and open.
PHP Version Support:
PHP 4, PHP 5, PHP 7, PHP 8
Summary: PHP is_object() Function
is_resource() is a built-in variable handling function. It is an easy function to determine whether a resource is still open and valid or not.