Class Uq_engines.output_engine

Generic output engine for writing to a file descriptor: let e = new output_engine f fd tmo - Waits until the file descriptor becomes writable, and calls then let x = f fd to write to the descriptor. The result x is the result of the engine.

If the file descriptor does not become writable within tmo seconds, the resulting engine transitions to `Error Timeout.

Use this class to construct engines writing via Unix.single_write or comparable I/O functions:

      let write_engine fd s tmo esys =
        new output_engine (fun fd ->
                             Unix.single_write fd s 0 (String.length s)
                          )
                          fd tmo esys
      

This engine returns the number of written bytes.

See also Uq_io.output_e for a more generic way of writing with engines.