PHP is_resource() Function

Check whether a variable is a resource or not:

<?php
$file = fopen("test.txt","r");

if (is_resource($file)) {
echo "File is open";
} else {
echo "Error open file";
}
?>

Definition and Usage

The is_resource() function checks whether a variable is a resource or not.

Note: The is_resource() function will return FALSE if the resource has been closed.

This function returns true (1) if the variable is a resource, otherwise it returns false/nothing.

is_resource( variable);

Parameter	Description
variable	Required. Specifies the variable to check

Return Value:	TRUE if variable is a resource, FALSE otherwise
Return Type:	Boolean
PHP Version:	4.0+