New to Ruby needs help

[Beginner]

Dear Gurus,

I would like to call a Win32API dll from ruby and I did the following:

require 'Win32API'
dwtest = "" * 8
shell1=Win32API.new("my.dll", "myfunc",['P','P','P'],'L')

myfunc takes 3 parameters, &dwerror, &dwnum, &dwtest. Return value is 0
or 1.

I would like to print or test "&dwtest" which is the 3rd parameter, but
I don't know what mistake am I doing, it never prints the right value.
I even did "unpack" using dwtest.unpack('L').

Could you pls modify the above code?

Any help is appreciated.

thx,
Mankan