System task or function '$value$plusarg' is not defined -> Warning : Verilog

Question

I am trying to learn how to use $value$plusarg. I have picked up the following code from somewhere.

module test;
integer i, r;

initial begin
  r = $value$plusarg("myint=%d", i);
  $display("Value is %0d", i);
end

endmodule

When I tried to run it, I am getting the warning as:

System task or function '$value$plusarg' is not defined.

I have used Modelsim. The commands I have used are as follows:

vlog test_genvar.v +define+myint="22"
vsim work.test
run -all

I am not sure if the problem is with the code or the commands I have used. Thanks in advance :)

Answer 1

Very silly mistake. The system task name is $value$plusargs and not $value$plusarg (missing 's'..!!!).

Moreover, you may use $test$plusargs to detect/test whether the given switch is available at run-time or not. Like as follows:

if($test$plusargs("myint"))
begin
$value$plusargs("myint=%d",i);
end

One more thing, I am using VCS, and to provide these kind of switches, I use simply "./simv +myint=5" (of course simv is my compiled-executable file). So, no need of +define+myint=5, directly +myint=5 should work.

Also, these are run-time switches and not compile time. So, I think they should be with vsim command and not vlog, but I am not sure about this. Not big deal, I guess.

Your code is available here at EDAPlayground, simulated with VCS. Just for reference.