I have to make a programm to read DATA from a Card, the first function that I must call says:
Function_name(hcaller As Long,...)
This hcaller is an hWnd and should say which window handler calls the function. What does this mean?
An hWnd is a pointer to a window in the Windows environment. Every window on the screen has an hWnd value. Visual Basic exposes this property through the hWnd property that is part of every Form object. Try passing the hWnd property of the current form to the API call.