Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

Chapter 8 193
Intrinsics Reference
FCONTROL(37)
FCONTROL(37)
Parameters
controlcode 37 — Sets both terminal type and speed.
param 16-bit unsigned integer by reference
(required)
Passes a value which specifies a new line speed and
terminal type to be associated with an asynchronous
port. Bits (0:11) specify the speed, bits (11:5) specify the
terminal type.
Notes This use of the FCONTROL intrinsic stems from an
early point in the development of Hewlett-Packard
operating systems when it was necessary to allocate a
terminal before it could be opened programmatically.
This is no longer necessary, but the intrinsic is still in
use today and allows you to programmatically set both
terminal type and speed for a terminal through a single
call. Both of these values can be set individually
through other FCONTROL calls.
When you use FCONTROL(37), param passes the
desired speed and terminal type values. The speed is
represented in characters per second and is contained
in bits (0:11). The terminal type is contained in bits
(11:5).
You must be sure the speed associated with a device
matches the physical speed setting of the device and of
the modem, if a modem is part of the device connection.
If you programmatically change the speed of a device
your program should request that the speed setting be
manually changed at the device as well.
You cannot use FCONTROL(37) to set the terminal to
an unsupported speed or terminal type. Attempting to
do so will cause an error condition of CCL. You cannot
use FCONTROL(37) with user-defined terminal types.
You must call FDEVICECONTROL to specify the
terminal type when using a terminal type defined
through the Workstation Configurator.