[DUG] Dll issue

[Robert martin]

Thanks Rohit

Trapping the exception in the dll and trying to show the message also 
fails (the app still disappears).  But a good suggestion (Should have 
tried that 'much' earlier.

 Rob Martin
Software Engineer

phone +64 03 377 0495
fax   +64 03 377 0496
web www.chreos.com

Wild Software Ltd



Rohit Gupta wrote:
> I dont know about widestrings, but ansistrings can be a problem with 
> dlls.  Also note that if written in Delphi you have to handle all 
> exceptions inside the dll.... as the exception itself uses ansistring.
>
> Robert martin wrote:
>> Hi again
>>
>> Further to my previous email I want to check that I have this right.  
>> I think I am doing something wrong in relation to passing variables.
>>
>> My dll Call is defined as
>>
>>  TRunEFTPOS = Function(var Amount, CardType, ResCode: WideString; 
>> Account, MercRef, TransRef, HeaderLine, FooterLine : WideString) : 
>> Boolean;
>>
>> Note is users var parameters.
>>
>>
>> This is my test calling code
>>
>> var
>>    RunIt           : TRunEFTPOS;
>>    EFTPOSHandle    : THandle;
>>    ARes            : WideString;
>>    CardType        : WideString;
>>    iRes            : Integer;
>>    Amt             : Extended;
>>    TestAmt         : WideString;
>>    Authorised      : Boolean;
>> begin
>>  inherited;
>>    //RUN DLL
>>
>>    CardType := '';
>>    Amt :=  10.95;
>>    TestAmt := FloatToStr(Amt);
>>
>>    EFTPOSHandle := LoadLibrary('EftPos.dll');
>>    if (EFTPOSHandle <> 0) then begin
>>        try
>>            @RunIt := GetProcAddress(EFTPOSHandle, 'RunIt');
>>
>>            if (@RunIt <> nil) then begin
>>                Authorised := RunIt(TestAmt, CardType, ARes, '1', '1', 
>> '12345' , 'Test eftpos', 'Test');
>>                iRes := StrToIntDef(ARes, -1);
>>
>>                if (Authorised = True) then begin
>>
>>                    ShowMessage(TestAmt);
>>                end;
>>            end;
>>        finally
>>            FreeLibrary(EFTPOSHandle);
>>        end;
>>    end;
>>
>>
>>
>>
>> Could passing var parameters be the root cause of my problem?  (This 
>> Dll was working fine previously)
>>
>> Also the calling app has Sharemem in the uses clause but the dll does 
>> not.  Adding it to the dll causes an av 'after' running the dll in 
>> the test app, the main app still dies at the start.
>>
>> Any comments would be appreciated.
>>
>>
>>
>>
>> Rob Martin
>> Software Engineer
>>
>> phone +64 03 377 0495
>> fax   +64 03 377 0496
>> web www.chreos.com
>>
>> Wild Software Ltd
>>
>>
>>
>> Robert martin wrote:
>>> Hi
>>>
>>> I have been using a (home made) DLL to interface between our app and 
>>> an eftpos systems ActiveX control.  All worked well until we updated 
>>> their software.  Now my app blows away when I try to create the 
>>> ActiveX (in the dll).  However after much testing I have discovered 
>>> if I call the dll from behind a TAdvGlowButton (fancy glowing 
>>> button) it works ! but I get an error in GDIPlus.dll after the first 
>>> time.
>>>
>>> It seems to be some sort of issue between the dlls being used 
>>> (GDIPlus.dll and eftpos.Dll
>>>
>>> Any ideas ?
>>>
>>>
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>>
>
> -- 
> *Rohit Gupta*
> * B.E. Elec.   M.E.   Mem IEEE    Associate IEE*
> *Technical Manager*
> *Computer Fanatics Limited*
> ** 
> *Tel*     +64 9 4892280
> *Fax*    +64 9 4892290
> *Email  *rohit at cfl.co.nz <mailto:rohit at cfl.co.nz>**
> *Web    *www.cfl.co.nz <http://www.cfl.co.nz/>
>  
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