ReadWriteFDHandle

:::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. :::

Interface Synopsis

namespace HH\Lib\IO;

interface ReadWriteFDHandle implements WriteFDHandle, ReadFDHandle, ReadWriteHandle {...}

Public Methods (HH\Lib\IO\FDHandle)

• ->getFileDescriptor(): \HH\Lib\OS\FileDescriptor

Public Methods (HH\Lib\IO\WriteHandle)

• ->writeAllAsync(string $bytes, ?int $timeout_ns = NULL): Awaitable<void>
  Write all of the requested data
• ->writeAllowPartialSuccessAsync(string $bytes, ?int $timeout_ns = NULL): Awaitable<int>
  Write data, waiting if necessary

Public Methods (HH\Lib\IO\ReadHandle)

• ->readAllAsync(?int $max_bytes = NULL, ?int $timeout_ns = NULL): Awaitable<string>
  Read until there is no more data to read
• ->readAllowPartialSuccessAsync(?int $max_bytes = NULL, ?int $timeout_ns = NULL): Awaitable<string>
  Read from the handle, waiting for data if necessary
• ->readFixedSizeAsync(int $size, ?int $timeout_ns = NULL): Awaitable<string>
  Read a fixed amount of data
• ->readImpl(?int $max_bytes = NULL): string
  An immediate, unordered read

Protected Methods (HH\Lib\IO\WriteHandle)

• ->writeImpl(string $bytes): int
  An immediate unordered write