From: jeepcreep <jeepcreep@...>
Date: 2004-01-11T02:44:48+09:00
Subject: Please unsubscribe

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Content-Type: text/plain; charset=us-ascii

Please unsubscribe

Shashank Date <sdate@everestkc.net> wrote:Ruby/Win Gurus,

I haven't figured out how to dereference pointers passed in as arguments
to Win32 API. For example, in the following call (in C) to NetStatisticsGet
API (which may be broken on NT, but that is not the point here).

LPBYTE lpBuffer;
int ret;
ret = NetStatisticsGet (
NULL,
(char *)is_workstation ? L"LanmanWorkstation" : L"LanmanServer"),
0,
0,
&lpBuffer);

The last parameter lpBuffer is a pointer to a pointer.
The API call internally allocates memory and sets the value of the pointer
to the
variable whose pointer you have passed in. It is your responsibility to free
the
memory using NetApiBufferFree function.

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?

TIA,
-- shanko





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