DLL calling convention prob

My friend had written a DLL with C from which we are calling some functions in VB. The following is the code we're using but every time it gives us runtime errors - 'DLL Calling Convention Error'..

Can anyone enlighten us?

Global flagName As String

Public Declare Function getFlagState Lib "edrlib" (ByVal flagName As String) As Long


Private Sub Form_Load()
    e = getFlagState(flagName) 'error here
End Sub

Even any little pointers?? Is the problem in our DLL - it may be to do with the string data type...

Cheers!
Mafro

[Edited by Mafro on 05-26-2000 at 10:27 AM]

[Sam Finch]

it could well be with the string, passing it byval to C++ is right, when you get it in C++ you get a long pointer to a char array, is this what yu were expecting? If not change the dll.

[Frans C]

Don't forget to initialise the string before passing it to the dll.
eg
flagName = space(255)
e = getFlagState(flagName)

The DLL has been tested in C with another program and works fine - my friend that wrote the DLL says he was expecting a long pointer to a char array.. This is the function prototype from the DLL:

int __declspec(dllexport) __cdecl getFlagState(LPSTR flagName);

Also, the flagName variable has a value when it is passed to the function, so we don't need to initialise it..

Would anyone mind having a look at the DLL and the program as it stands??

Thanks!!