RE: [Help-glpk] VBA/dll for Excel

[Meketon, Marc]

Thanks.

I produced a DLL as well by adding __stdcall __export to the right
function calls.  [BTW, I'm using the free Turbo C++ compiler from
Borland.]

BUT, I cannot seem to get the callback function for "glp_term_hook" to
properly work.  Before I begin to setup the problem, I use very similar
VBA code to what the Version 10 of the Informatiks software uses:

  Const MAXMSG as long = 500
  Private ActMsg as long

  Private Messages(MAXMSG) as string

  Public sub INIT_GLPK()
    Dim info as long

    info = 0
    glp_term_hook AddressOf MessageHandler, info
    ActMsg = 0
  end sub

and

  public function MessageHandler(ByVal info As Long, ByVal msg As Long)
As Long
    Dim l As Long
    Dim Err_Message As String

    On Error Resume Next

    If ActMsg < MAXMSG Then
        ActMsg = ActMsg + 1
    End If
    l = lstrlen(msg)
    Err_Message = Space$(l + 1)
    lstrcpy Err_Message, msg
    Err_Message = Left(Err_Message, l)
    Messages(ActMsg) = Err_Message

    MessageHandler = 1
  End Function

However, when the "xputs" function in GLPK tries to return, the code
bombs.  The "xputs" does call the "MessageHandler", and it seems to pass
in the correct string, and xputs does see the correct return.  I believe
that somehow the stack gets messed up a bit, but I haven't figured out
any workaround.

Any ideas on how to successfully invoke the call-back function for the
terminal hook?

-Marc
-----Original Message-----
From: Xypron [mailto:address@hidden 
Sent: Tuesday, March 18, 2008 10:53 AM
To: Meketon, Marc
Cc: address@hidden
Subject: Re: [Help-glpk] VBA/dll for Excel

Hello Marc,

couldn't You use the DLL produced by
w32/Build_GLPK_with_VC6_MT_DLL.bat
with Visual C++ 7.0 or 6.0?
(see ftp://glpk.dyndns.org/glpk/glpk_4_27.dll.tar.gz)

Best regards

Xypron

Meketon, Marc wrote:
>
> A while back there was a version of GLPK for VBA applications (such as

> in Excel). That was based on version 10 of GLPK. Does anyone work with

> GLPK in VBA with a recent version of the software? If so, can you 
> please provide links? It appears that the original folks (Informatik 
> Fuchs) do have a version 23, but it's on a CD for 50 euros, and there 
> is no English page for it, so I'm not sure how possible it will be for

> me to get the CD.
>
> FYI, the German web page for the version 10 VBA implementation is: 
> http://www.informatikfuchs.de/Software/GLPK/glpkVBDownload.htm (and 
> there is a link for the English version of this web page on this
page).
>
> -Marc Meketon
>
>
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