class call_engine :This engine corresponds to?ignore_error_code:bool -> ?mode:Shell_sys.group_mode -> ?stdin:Shell.producer -> ?stdout:Shell.consumer -> ?stderr:Shell.consumer -> Shell_sys.command list -> Unixqueue.event_system ->[Shell_sys.job_status]job_handler_engine_type
Shell.call. The command list is
executed until the job is done. In this case,
the status of the engine changes to `Done or `Error.
If not ignore_error_code, failed jobs are reported by the
error status `Error Subprocess_failure. If ignore_error_code,
failed jobs are ignored, and result in the status `Done
(however, jobs terminated by signals are still reported as
errors).
For the other arguments see Shell.call.
When the engine goes to `Error or `Aborted, the job
is terminated ( Shell_sys.abandon_job ).
