Specifies the type of flow control used to regulate the flow of
data to a hardcopy device.
| Used in: |
GOPTIONS statement; GDEVICE procedure; GDEVICE Parameters window
|
| Default: |
host dependent
|
|
HANDSHAKE=HARDWARE | NONE | SOFTWARE | XONXOFF
|
-
HARDWARE
HARD
-
specifies that SAS/GRAPH instruct
the device to use the hardware CTS and RTS signals. (This is not appropriate
for some devices.)
-
NONE
-
specifies that SAS/GRAPH send
data without providing flow control. Specify NONE only if the hardware or
interface program you are using provides its own flow control.
-
SOFTWARE
SOFT
-
specifies that SAS/GRAPH use
programmed flow control with plotters in eavesdrop mode.
-
XONXOFF
X
-
specifies that SAS/GRAPH instruct
the device to use ASCII characters DC1 and DC3. (This is not appropriate
for some devices.)
HANDSHAKE regulates flow of control by
specifying how and if a device can signal to the host to temporarily halt
transmission and then resume it. Flow control is important because it is possible
to send commands to a hardcopy device faster than they can be executed.
HANDSHAKE can be used when you are using a protocol
converter, interface program, or host computer that can perform XONXOFF or
hardware handshaking. You also can use this option if you are routing output
through flow-control programs of your own, as in a multiple-machine personal
computer environment where the graphics plotter is a shared resource. SAS/GRAPH software
sends output to a server (the file transfer does not require flow control).
The server queues incoming graphs and sends them to the plotter. The server,
rather than SAS/GRAPH software, is
responsible for handling flow control.
If you do not use HANDSHAKE, the value in the driver
entry is used.
If you use HANDSHAKE=XONXOFF or HANDSHAKE=HARDWARE, SAS/GRAPH does
not actually do the handshaking. It tells the device which type of handshake
is being used. The protocol converter, interface program, or host computer
actually does the handshake.
Note:
If you are creating
a graphics stream file using a driver for a plotter and you specify HANDSHAKE=SOFTWARE,
the software that you use to send the file to the plotter must be able to
perform a software handshake. You will probably want to specify one of the
alternative values if you route output to a file. ![[cautend]](../common/images/cautend.gif)
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
