From: Park Heesob <phasis@...>
Date: 2004-01-11T08:37:11+09:00
Subject: Re: dereferencing pointers in Win32 API

Hi,
>
> Thanks for looking.
>
> "Dennis Ranke" <exoticorn@epost.de> wrote in message
> > 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.
>
> I tried that and i get:
>
> C:/atest/tst_netapi32.rb:28:in `unpack': no associated pointer
> (ArgumentError)
>  from C:/atest/tst_netapi32.rb:28
>
Just use memcpy.
Try this code.

require "Win32API"

SERVICE_WORKSTATION = [
76,0,97,0,110,0,109,0,97,0,110,0,87,0,111,0,114,0,
107,0,115,0,116,0,97,0,116,0,105,0,111,0,110,0,0,0]


SERVICE_WORKSTATION.each{|e| print "%c" % e if e > 0}
puts

service = SERVICE_WORKSTATION.pack("U*") # Unicode

NetStatisticsGet = Win32API.new('netapi32','NetStatisticsGet','PPNNP','I')

bufptr = "\0" * 4
ret = NetStatisticsGet.call(0,service,0,0,bufptr)

if 0 != ret
  puts "Failed:#{ret}"
  exit
end

STAT_WORKSTATION_SIZE =  (13*8) + (28*4)

rbuf = "\0" * STAT_WORKSTATION_SIZE
memcpy = Win32API.new('msvcrt','memcpy','PPL','P')
memcpy.Call(rbuf,bufptr,STAT_WORKSTATION_SIZE)

struct = rbuf.unpack("L*")
p struct

__END__

Regards,

Park Heesob