dll question 1

[bernardsylunar]

hi everyone!

i'm new to Visual C++ and i try to create my own dll and call it from my Visual Basic 6.0 program. i've created a function IsStringEqual that will check if the two strings are equal. here's my code...

In Visual C++

int _stdcall IsStringEqual(char string1, char string2, int discardCase)
{
if (discardCase == 1)
{
string1 = tolower(string1);
string2 = tolower(string2);
}
if (string1 == string2)
return 1;
else
return 0;
}


In Visual Basic

Private Declare Function IsStringEqual Lib "E:\ynad\personal\program\vc++\MyDll\Release\MyDll.dll" (ByVal String1 As Any, ByVal String2 As Any, ByVal discardCase As Integer)

Private Sub Command1_Click()
Dim i
i = IsStringEqual(Text1.Text, Text2.Text, 0)
Debug.Print i
End Sub

-------------------------------------

everytime i run my visual basic project and click the command button there's always an error message 'Bad DLL calling convention'. i try to remove the _stdcall there's always the same error that i've encountered.

pls help...

thanks in advance

ynad
----
It is foolish to listen to someone who will not listen to you.

 

[xwb]

I think Text maps to char*. Try

#include <string.h>
int _stdcall IsStringEqual(char* string1, char* string2, int discardCase)
{
    if (discardCase == 1)
        return _stricmp (string1, string2) == 0;
    else
        return strcmp (string1, string1) == 0;
}

 

[bernardsylunar]

xwb

thanks for your reply. i've copy and paste your code the still i got same error.

thanks again...

ynad
----
It is foolish to listen to someone who will not listen to you.

 

[LazyMe]

From the code snippet it is diffcult to see whether you're using 1 or 2 underscores in _stdcall. Have you tried with two? Better yet; use WINAPI, which resolves to the correct one dependent on your target platform, if i'm not mistaken...

And have you tried replacing the Any arguments with string arguments?



Greetings,
Rick

 

[bernardsylunar]

Hi Rick

Thnks for the reply.

i already tried replacing String with Any before and it did not work.

as you have said, i try using two underscores but i got the same error...

by the way, i'm still working on it anyway. i hope i can make it work a.s.a.p...

many thanks for your reply..




ynad
----
It is foolish to listen to someone who will not listen to you.

 

[LazyMe]

One more thing; did you link a module definition file with the dll? This is used to export the functions inside your dll.

Greetings,
Rick

 

[bernardsylunar]

yes, i included IsStringEqual in the EXPORTS list on the .def file

thanks




ynad
----
It is foolish to listen to someone who will not listen to you.

 

[LazyMe]

Last shot (it's that I don't have much time to test your stuff):

I see that your declare does not return a function return type; this will make it a variant by default, right? Variants are not 4 bytes (which is what your C function returns).

If this doesn't help; in the weekend I'll try to make the two projects you're making....

Greetings,
Rick

 

[bernardsylunar]

hi Rick,

you got it dude!!!

the return value in my VB declaration is what i missed.

a star for you!!!

btw, i got another problem. i try to register my dll but there's an error.

C:\MyDll.dll was loaded, but the DllRegisterServer entry point was not found.

DllRegisterServer may not be exported, or a corrupt version of C:\MyDll.dll may be in memory. Consider using PView to detect and remove it.

any idea on this?

thanks again...






ynad
----
It is foolish to listen to someone who will not listen to you.

 

[LazyMe]

It probably is a regular dll, and not a COM dll. Therefore it need not and can not be registered (if it were a COM dll you wouldn't need to use the declare from within VB, would you?)

Greetings,
Rick

 

[bernardsylunar]

oh i get it. i thought every dll should be first registered before using. i just copy it into the windows/system32 and it's working.

thanks a lot..

and thanks for the help...

another star

ynad
----
It is foolish to listen to someone who will not listen to you.