From: warhero <beingthexemplarylists@...>
Date: 2006-12-04T14:55:07+09:00
Subject: utilizing dlls in windows programming?

This is a two part question:

I have been reading the pick-axe book and was reading the chapter on
ruby and windows. I was reading documentation on the DL library. (is
library the correct term for that?), but my question: what is the
difference in the Win32API and using say DL.dlopen? Also in reading the
documentation on the Win32API in the back of the book, it said that
Win32API is more than likely going to be phased out.


My second question:

I am trying to utilize a DLL that is for phidgets (phidgets.com). They
have a dll (phidget21.dll) that is supposed to be used to gain access
to controlling their hardware. I've looked at their documentation for
the C language. Is that usually what a dll is written in? C? You can
download what I am looking at from the documentation section. (The C
API Manual ). I've tried a couple of different ways to try and use the
dll. Nothing as succeeded. I've tried the Win32API and the DL.dlopen.
It's probably just the way i'm trying to use it. here is what im
trying:

require "dl"
Phidget21 = DL.dlopen("phidget21");
f = Phidget21["CPhidgetRFID_create", "S"]
handle = f.call()
open = Phidget21["CPhidget_open", "II"]
open.call( 25807 )

The first problem is that handle = nil. Besides that, I don't
understand fully how to be passing back and forth parameters to the
dlls. This example cause the interactive ruby to crash (terminates in
an unusual way). I know this isn't all that's needed to work with the
phidgets, but i'm just trying to go step by step and even get it setup
correctly.

download the phidget21.dll
(http://www.smithaaronlee.net/downloads/phidget21.dll), i've posted the
dll online. Also, here is a direct link to the C API
:http://www.phidgets.com/documentation/C_API_Manual_Phidget21.pdf

any help, hints or tips would be much appreciated.

thanks