ReadImpl

:::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. :::

An immediate, unordered read

public function readImpl(
  ?int $max_bytes = NULL,
): string;

Parameters

• ?int $max_bytes = NULL the maximum number of bytes to read
• if null, an internal default will be used.
• if 0, EINVAL will be raised.
• up to $max_bytes may be allocated in a buffer; large values may lead to unnecessarily hitting the request memory limit.

Returns

• string