PHP apcu_clear_cache() Function: Usage and Examples

Removes all user entries from the current APCu cache instance.

What It Does and When to Use It

Clear user-cache entries and check the result. APCu stores local application data, Redis is external and can be shared among hosts, and OPcache stores compiled code.

Requirements, Inputs and Expected Behavior

Confirm the runtime, extension, environment variables, and permissions before running the examples in production. It is a broad invalidation operation; prefer deleting targeted keys when possible.

Example 1: Basic Operation

Clear user-cache entries and check the result.

<?php
if (!apcu_clear_cache()) throw new RuntimeException('APCu clear failed');

Example 2: Behavior and Validation

Show that a cache-wide clear removes previously stored data.

<?php
apcu_store('report:v1', ['items' => 3], 60);
 apcu_clear_cache();
 var_dump(apcu_fetch('report:v1', $found), $found);

Practical Example: Application Use

Restrict operational cache clearing to trusted maintenance contexts.

<?php
if (isset($_SERVER['REQUEST_METHOD'])) {
     throw new RuntimeException('Do not publish cache reset as an unauthenticated HTTP endpoint');
 }
 echo apcu_clear_cache() ? 'Cleared' : 'Failed';

Important Behavior and Edge Cases

The second example highlights: Show that a cache-wide clear removes previously stored data. The practical example adds: Restrict operational cache clearing to trusted maintenance contexts.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Removes all user entries from the current APCu cache instance.
• Restrict operational cache clearing to trusted maintenance contexts.
• Define TTL, invalidation, and concurrency behavior separately from the cache storage API.