Passing string variables to plusargs

Question

I need to get command line options to add conditions to constraints in SystemVerilog.

I'm invoking $value$pluargs("string=%d",val) from a function call, and I need to use the parameter passed to the function as the 'string' name.

function(string name);
$value$plusargs("<name>=%d", val)
endfunction

I'm not sure how to do this. Saying $value$plusargs("%s=%d",name,val) results in a 'too many arguments' error.

Answer 1

You can use string concatenation:

module tb;
    int val = 5;

    initial begin
        $monitor("val=", val);
        foo("bar");
    end

    function void foo (string name);
        $value$plusargs({name, "=%d"}, val);
    endfunction
endmodule

Answer 2

You can use $test$plusargs to determine whether the command line switch is provided or not.

This system function searches the list of plusargs for the provided string. The plusargs present on the command line are searched in the order provided.

If all characters in the provided string, a result of 1'b1 is returned. If no plusarg from the command line matches the string provided, the result of 1'b0 is returned. I've modified the function, a little.

function void foo (string name);
    if( $test$plusargs("name") )
    begin
    // Use the below
    $value$plusargs({name, "=%d"}, val);
    end
endfunction