Channel¶
A channel is a typed, synchronized queue used to pass values between concurrent tasks, popularized by Go’s chan and modeled on Communicating Sequential Processes, CSP: rather than sharing mutable memory protected by locks, tasks communicate by sending values through a channel, and the channel itself provides the necessary synchronization. A send can block until a receiver is ready, and a receive can block until a value is sent, depending on whether the channel is buffered.
CSP-style concurrency treats the channel, not the lock, as the primary coordination primitive, and languages built around it, in Go, in Clojure’s core.async, with Erlang-style message passing, encourage structuring concurrent programs as independent tasks connected by channels rather than as threads sharing state.
PHP has no native channel type. Concurrency primitives such as Fiber provide cooperative multitasking within a single thread, but communication between fibers or between processes must be built from lower-level tools: a SplQueue, a message queue extension, shared memory, or a userland library; none of these are integrated into the language as a first-class, typed, blocking channel the way Go’s chan is.
Related : Fibers, Coroutine, Queue, Thread, Shared Memory, Async
