From: Dennis Ranke <exoticorn@...>
Date: 2004-01-11T03:36:40+09:00
Subject: Re: dereferencing pointers in Win32 API

On Sat, 10 Jan 2004 11:26:59 -0600, Shashank Date <sdate@everestkc.net> 
wrote:

> When I call this in Ruby, I do the following:
> #----------------
>
> netStatisticsGet = 
> Win32API.new('netapi32','NetStatisticsGet','PPNNP','I')
>
> lpBuffer = ' ' * 4 # area to store the pointer value
>
> # assume that the variable 'service' contains "LanmanWorkstation" in 
> Unicode
> ret = netStatisticsGet.call(0,service,0,0,lpBuffer)
>
> #-----------------
>
> This call succeeds (because I get ret == 0) which means lpBuffer now 
> points
> to the
> buffer in memory. My questions is how do I de-reference this variable in
> Ruby?

If I'm not completely wrong, you should be able to dereference it using 
lpBuffer.unpack('P<size>') where <size> is the size of the buffer in 
bytes. Just remember that unpack returns an array, the first element of 
which will be the dereferenced buffer as a string.

-- 
Dennis Ranke