Atomically decreases a cached integer.
What Is apcu_dec() in PHP?
Atomically decreases a cached integer.
Its syntax is:
apcu_dec(string $key, int $step = 1, ?bool &$success = null, int $ttl = 0): int|falseParameters:
$key— Accepted as string; required argument.$step— Accepted as int; optional default 1.$success— Accepted as ?bool &; optional default null.$ttl— Accepted as int; optional default 0.
Return type: int|false. This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success.
Availability: Requires APCu enabled for the current PHP SAPI.
Example 1: Basic Usage
<?php
apcu_store("stock", 12);
echo apcu_dec("stock");
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success.
Example 2: A Different Input
<?php
apcu_store("quota", 10);
echo apcu_dec("quota", 3);
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success.
Practical Example: Applying It in a Program
<?php
apcu_store("remaining", 8);
$remaining = apcu_dec("remaining", 2, $operationSucceeded);
if ($operationSucceeded) { echo "Remaining: " . $remaining; }
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success.
Important Behavior and Edge Cases
- Key behavior: This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success.
- Environment: Requires APCu enabled for the current PHP SAPI.
Comparison With Related Functions
| Function | Purpose |
|---|---|
apcu_dec() | atomically decreases a cached integer. |
apcu_inc() | apcu_inc() increases a numeric cache entry; apcu_dec() decreases it. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Ignoring this behavior: This only operates on compatible cached numeric values | This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success. |
Key Takeaways
- atomically decreases a cached integer.
- This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success.
- Requires APCu enabled for the current PHP SAPI.
Summary: This only operates on compatible cached numeric values. Check the success flag rather than interpreting every return value as success.