reference appendices

Resource Types

A PHP resource is a handle to an external asset such as an open file, stream, or process. Resources are not ordinary objects, and their lifecycle matters in long-running processes.

Use This Reference When

Opening and closing files.
Reading legacy extension APIs that return resources.
Debugging leaked handles in workers or batch jobs.

Close an Open File

PHP example

<?php

$handle = fopen('php://memory', 'w+');
fwrite($handle, "php\n");
rewind($handle);
echo stream_get_contents($handle);
fclose($handle);

// Prints:
// php

Check each function’s return type because many resource-producing APIs return false on failure. Close resources promptly when ownership is clear.

Practice

Handle an Open Failure

Open a file for reading, check the return value, and close the handle after use. Describe which layer owns cleanup.

Show solution

Check if ($handle === false) before reading. The code that successfully opens the handle should usually ensure it is closed, often with finally when later operations can fail.