Request Error

:::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. :::

Return the error output handle for the current request

namespace HH\Lib\IO;

function request_error(): ?CloseableWriteFDHandle;

This is usually only available for CLI scripts; it will return null in most other contexts, including HTTP requests.

For a throwing version, use request_errorx().

In CLI mode, this is usually the process STDERR.

Returns

• ?CloseableWriteFDHandle