beautypg.com

Var: modify or query system variables – Sierra Video Pro XL Series 8 User Manual

Page 58

background image

SIERRA VIDEO


52

VAR: Modify or query system variables

Action From

Syntax

Modify

Host

G

VAR,,[,…]~

Query

Host

G

VAR,~

Query Response

Router (same as Modify)


Modify is Protected:

Yes

Report Changes:

No

The “G VAR“ command is used to change or query system variables that control specific features
of the router. The variable being affected is specified using its name, and only one variable at a
time can be targeted by this command. The features being controlled are typically system
options that allow the user to control special hardware or software enhancements to the router
code.

The Modify command has two or more arguments, the name of the variable to be changed and
the new value of that variable. Most variables have only a single value associated with them, but
it is possible for a variable to be multi-valued, in which case the number of arguments
may be two or more.

The Query command has the variable name whose value is to be queried as the only argument.

The Query Response command has the same argument structure as the Modify command.

Each different router may support different variables. The supported variables may grow over
time, as enhancements are added to this protocol, so command parsers should generally ignore
unknown variable names. The routers themselves will ignore any command that is received with
an unknown variable name or an invalid variable value. Use the “G VARQRY” command to find
out which variables a particular router actually supports. Refer to documentation for each router
for a description of the variables.

A variable value is typically an unsigned decimal number, but may also be a signed decimal
number. The “G VARQRY” command can be used to determine the allowed range of values.

For example, to query for the value of a variable named “VI_DELAY”:

** G VAR,VI_DELAY~ !!

The response command might be:

** G VAR,VI_DELAY,4~ !!

To set the “HD_SLAVE” variable to 1:

** G VAR,HD_SLAVE,1~ !!