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writeAllowPartialSuccessAsync

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.

Write data, waiting if necessary

public function writeAllowPartialSuccessAsync(
  string $bytes,
  ?int $timeout_ns = NULL,
): Awaitable<int>;

A wrapper around write() that will wait if write() would throw an OS\BlockingIOException

It is possible for the write to partially succeed - check the return value and call again if needed.

Parameters​

  • string $bytes
  • ?int $timeout_ns = NULL

Returns​

  • the - number of bytes written, which may be less than the length of input string.