Article View: comp.os.ms-windows.programmer.tools.mfc
Article #72Re: HELP !!! WIth VB & DLL connection
From: Helge SΓΌΓ
Date: Tue, 09 Apr 1996 09:13
Date: Tue, 09 Apr 1996 09:13
43 lines
2167 bytes
2167 bytes
iti@Jerusalem.netvision.net.il wrote:
>
>I have a DLL written in Visual C++ and am trying to write a Visual Basic (Ver. >3) application to use it. I am new to VB so I have two questions.
>
> 1. How can I access the message que (in order to do my own message >processing) in a VB application?
>
> 2. I have a C DLL function declaired as
>"char far* WINAPI _export MyFunct(void) ". How do I declare it in VB.
>
Declare Function MyFunct Lib "MyDll.DLL" As Long
You won't be happy with the char* though because VB Strings are handled
in a VERY different way. If you want to return a string result pass a
pointer to the function and a pre-initialized string at runtime.
e.g. int WINAPI _export MyFunct(char* result);
Declare Function MyFunct Lib "MyDll.DLL" (ByVal result As String) As Integer
(if you want to return a negative error code as function result in the int
or the length of the string if successful)
Then call it like this:
Dim ok As Integer
Dim resultstring As String
resultstring = "lotsofspacesuptothemaxyou'llexpect" & chr$(0)
ok = MyFunct(resultstring)
If ok >= 0 Then
resultstring = Left$(resultstring, ok)
Else
' got some error to report
End If
Helge ;-)=)
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(c) All Thoughts are Mine -- Genuine Genius
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helge@siemens.co.at ----- VIENNA -- AUSTRIA
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Path: arc1-ca.pugleaf.net!siemens.at!usenet From: "Helge SΓΌΓ" <helge@siemens.co.at> Newsgroups: comp.os.ms-windows.programmer.tools.mfc,comp.lang.c++,comp.lang.basic.visual.database,comp.lang.basic.visual Subject: Re: HELP !!! WIth VB & DLL connection Date: 9 Apr 1996 09:13:41 GMT Organization: Siemens AG Austria Message-ID: <4kd9o5$o15@news.siemens.at> References: <NEWTNews.31178.827960329.Postmaster@Jerusalem.netvision.net.il> NNTP-Posting-Host: pc5888.hil.siemens-austria Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 1.22 (Windows; I; 16bit) To: iti@net.netvision.il