From: daz <dooby@...10.karoo.co.uk>
Date: 2004-07-14T04:57:21+09:00
Subject: Re: win32api: how to access NetFileEnum results?


Jos Backus wrote:
>
> On Tue, Jul 13, 2004 at 04:32:23PM +0900, daz wrote:
>
> Next question is: using Pmemcpy1, how do I initialize the src POINTER_POINTER
> argument (i.e.  bufptr)? Setting it to 0 causes ruby to segfault (both 1.8.1
> and today's 1.8.2 snapshot installed using the one-click installer) and
> setting it to "\0" * 4 causes a TypeError as the template specifies a Long
> and I'm supplying a String.
>

Re-reading the API suggests a change of tack.
I think that memcpy isn't required.

bufptr needs to be POINTER to return_struct, so:

## rbuf          = "\0" * 10240            # return_struct
## bufptr        = [rbuf].pack('P')        # POINTER to rbuf (as packed string)

## NetFileEnum needs a POINTER to bufptr   # Win32API 'P' template will handle that

So my (UNTESTED) interpretation is:
#----------------------------------
require 'Win32API'

MAX_PREFERRED_LENGTH = -1
level = 3
entriesread   = "\0" * 4
totalentries  = "\0" * 4
resume_handle = "\0" * 4

rbuf          = "\0" * 10240  # testing, should be *entriesread * sizeof(FILE_INFO_3)
bufptr        = [rbuf].pack('P')        # POINTER to rbuf (as packed string)

NetFileEnum = Win32API.new('netapi32', 'NetFileEnum', 'PPPNPNPPP', 'I')
ret = NetFileEnum.call(0,0,0,level,bufptr,MAX_PREFERRED_LENGTH,entriesread,totalentries,resume_handle)

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

p rbuf
#----------------------------------

Good or bad ?


daz