swoole-src

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<h1 align="center">Swoole</h1>

<p align="center">An event-driven networking engine and coroutine runtime for PHP</p>

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Swoole is a PHP extension for building persistent network services and concurrent I/O applications. Its C/C++ core provides an event loop, coroutine scheduler, servers, clients, and protocol implementations. The bundled PHP library adds connection pools, proxies, and higher-level utilities. Use Swoole for HTTP APIs, WebSocket applications, TCP/UDP gateways, and services that need to handle many connections without a separate PHP process for every request.

> **Version note:** `master` is the development branch for Swoole 6.3 and currently supports PHP 8.2–8.5. For production, choose a released version and check the [supported versions](docs/SUPPORTED.md) for its PHP compatibility and maintenance status.

## At a glance

| Capability | Main APIs | Typical use |
| --- | --- | --- |
| Event-driven servers | `Swoole\Server`, `Swoole\Event` | TCP, UDP, Unix sockets, connection events |
| Coroutines | `Swoole\Coroutine`, `Channel`, `Socket` | Concurrent I/O and task coordination |
| HTTP and WebSocket | `Swoole\Http\Server`, `Swoole\WebSocket\Server` | APIs, streaming responses, real-time messaging |
| Coroutine clients | `Swoole\Coroutine\Client`, `Swoole\Coroutine\Http\Client` | Calls to TCP and HTTP upstream services |
| Runtime hooks | `Swoole\Runtime` | Coroutine-aware behavior for supported PHP functions |
| Processes and shared data | `Swoole\Process`, `Swoole\Table`, atomics | Background work and interprocess state |
| Timers and system I/O | `Swoole\Timer`, `Swoole\Coroutine\System` | Scheduled work, file and process operations |

## How Swoole works

The Reactor watches sockets and other registered file descriptors, then dispatches events to callbacks. Servers can run multiple worker processes to use multiple CPU cores. Within a worker, coroutines let other tasks run while one task waits for supported I/O. Task workers provide a separate execution path for jobs that should not hold up request handling.

Coroutines are a concurrency tool, not automatic CPU parallelism. A CPU-intensive PHP loop still occupies its worker until it yields or finishes. Use worker or task processes, or optional thread support, when work needs parallel execution.

Swoole workers are long-lived. Global variables, static state, and open resou