SetOnIOWaitEnterCallback - Hhvm

:::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. :::

Set callback for when the scheduler enters I/O wait

Hack

final public static function setOnIOWaitEnterCallback(
  mixed $callback,
): void;

Parameters

mixed $callback - A Closure to be called when I/O wait is entered

Returns

void