From: Park Heesob <phasis68@...>
Date: 2006-05-25T11:59:46+09:00
Subject: Re: Ruby / DL problem



Hi,

>From: Bama Test <bamatest@yahoo.com>
>Reply-To: ruby-talk@ruby-lang.org
>To: ruby-talk@ruby-lang.org (ruby-talk ML)
>Subject: Ruby / DL problem
>Date: Thu, 25 May 2006 01:35:06 +0900
>
>I've got a DLL that I'm working on interfacing to  - i've got everything 
>working except for this one function.
>
>int CreateDataFile ( const char* csUserID,
>                                  const char* chOptionalTemplateFilePath,
>                                  const char* csPrefix,
>                                  const char* csSuffix,
>                                  char*& newFileID);
>
>the problem is with the newFileID parameter - it's defined as "points
>to the buffer that receives the string of the File ID created. Maximum
>length of this buffer is 20 bytes."
>
>I've tried defining the call as both
>@createfile = msg["CreateDataFile", "ISSSSP"]
>and
>@createfile = msg["CreateDataFile", "ISSSSS"]
>
>and then passing in the values like this
>x = ""
>ptr = DL.malloc(20)
>a = @createfile.call('eldon',x,x,x,ptr)
>
>the function runs successfully but I can't ever retrieve the value of
>the FileID created from ptr and from what I can tell It still looks
>empty. So I figure I must either be defining it incorrectly or passing
>it in the call wrong. From my memory of C the & is actually a pointer
>to a memory location, but there seems something in my memory that it
>might mean something different when referenced like this (it's been
>like 10 years since i did anything in C) and I've done a ton of google
>searches already.
>
>Any guesses as to what i might be doing wrong?
>
define like this
@createfile = msg["CreateDataFile", "ISSSSP"]

and call like this

ptr = "\0" * 20
a = @createfile.call('eldon',x,x,x,[ptr].pack("P"))
puts ptr


Regards,

Park Heesob