class output_command :?onclose:unit -> unit -> string ->
out_obj_channel
/bin/sh
, and data written to the channel is
piped to stdin of the command.
The method pos_out
returns the number of written octets.
When close_out
is invoked, the subprocess is wait
ed for. If the
process exits with code 0, the method returns normally. Otherwise,
the exception Command_failure
is raised. (The channel is closed
even if this exception is raised.)
onclose
: this function is called when the close_out
method is
invoked, just after the underlying descriptor has been closed.