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

Chapter 8 209
Intrinsics Reference
FDEVICECONTROL
Device Control Directives
The following is a list of all possible values for the parm1 argument,
the control directive associated with that value, and a description of the
operation of that control directive.
Value of parm1
Action
1 Specify terminal type or printer type file.
This directive specifies a new terminal type or printer
type file which describes the device to the device driver.
The terminal type or printer type file must be in the
format used by the TTUTIL utility.
The buffer parameter contains the filename of the
terminal type or printer type file. The length
parameter contains the length of buffer.
If this call is issued against a device connected via PAD,
DTC Telnet, Telnet/iX or VT, a CCE condition code is
returned and the terminal type or printer type file
associated with the device will be changed. However,
the device will continue to operate as if no device
control action took place.
2 Set read timeout value for the next read.
This directive specifies a timeout value to apply to the
next read requested. buffer contains the number of
seconds to wait before terminating the read. The read
data is transferred to the user buffer and the read
length is returned. It is the same as FCONTROL (4). A
value of 0 means do not timeout. This device control
effects only the next read.
If the timer expires before the read completes, the read
returns error status 22 (software timeout). This use of
the FDEVICECONTROL intrinsic is the same as a call
to FCONTROL (4).
For reads posted to devices connected via PAD, DTC
Telnet, or Telnet/iX, be sure to add enough time to
compensate for any delays caused by the network.
This call is not supported on devices connected via VT.
3 Set line speed for the device.
This directive sets the line speed for the device. The
speed is the same for input and output. It is the same
as FCONTROL (10, 11, 40). Valid buffer values are (in