Atomically increments a cached integer.
What Is apcu_inc() in PHP?
Atomically increments a cached integer.
Its syntax is:
apcu_inc(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. The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters.
Availability: Requires APCu enabled for the current PHP SAPI.
Example 1: Basic Usage
<?php
apcu_store("views", 5);
echo apcu_inc("views");
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters.
Example 2: A Different Input
<?php
apcu_store("visits", 2);
echo apcu_inc("visits", 4);
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters.
Practical Example: Applying It in a Program
<?php
$counterKey = "processed:jobs";
apcu_add($counterKey, 0, 3600);
$total = apcu_inc($counterKey, 1, $updated);
if ($updated) { echo "Processed: " . $total; }
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters.
Important Behavior and Edge Cases
- Key behavior: The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters.
- Environment: Requires APCu enabled for the current PHP SAPI.
Comparison With Related Functions
| Function | Purpose |
|---|---|
apcu_inc() | atomically increments a cached integer. |
apcu_dec() | apcu_dec() decreases a cached integer while apcu_inc() increases it. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Ignoring this behavior: The increment is atomic, but creating a missing key requires explicit attention | The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters. |
Key Takeaways
- atomically increments a cached integer.
- The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters.
- Requires APCu enabled for the current PHP SAPI.
Summary: The increment is atomic, but creating a missing key requires explicit attention. Do not use process-local caches as durable financial counters.