Stream Await

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Awaitable version of stream_select()

function stream_await(
  resource $fp,
  int $events,
  float $timeout = 0,
): Awaitable<int>;

Parameters

• resource $fp - Stream resource, must be backed by a file descriptor such as a normal file, socket, tempfile, or stdio. Does not work with memory streams or user streams.
• int $events - Mix of STREAM_AWAIT_READ and/or STREAM_AWAIT_WRITE
• float $timeout = 0 - Timeout in seconds

Returns

• int - - Result code STREAM_AWAIT_CLOSED: Stream is closed STREAM_AWAIT_READY: Activity on the provided stream STREAM_AWAIT_TIMEOUT: No activity (timeout occured) STREAM_AWAIT_ERROR: Error