Example
A resource is a special type of variable that references an external resource, such as a file, socket, stream, document, or connection.
$file = fopen('/etc/passwd', 'r');
echo gettype($file);
# Out: resource
echo $file;
# Out: Resource id #2
There are different (sub-)types of resource. You can check the resource type using get_resource_type():
$file = fopen('/etc/passwd', 'r');
echo get_resource_type($file);
#Out: stream
$sock = fsockopen('www.google.com', 80);
echo get_resource_type($sock);
#Out: stream
You can find a complete list of built-in resource types here.
