Problem of writing a console function

Hello,

I start to write my console function, what I did it something like this:

In C++ code, I wrote:

ConsoleFunction(GetPixelScale, F32, 1, 1, "My function")
{
return dglGetPixelScale();
}

In my script, I wrote:

function ProcessCommandKey()
{
%i = GetPixelScale();
}

and when the script called function ProcessCommandKey(), the console output an error message which said that it cannot found the function GetPixelScale. Can anyone give me a hand if you know what am I doing wrong?

By the way, I defined my console funciton in dgl.cc

Thanks!!!
Nachi