Every time I try compile a VB project that uses a Delphi (2007) activex, I get a DAX error in the delphi activex. This only happens when I try to compile the VB project.
Anybody knows what might be going on?
+4
A:
Read of address 00000000 is a null pointer dereference. Most likely, that means that somewhere inside the library, something's trying to use an object that hasn't been constructed or assigned yet.
This type of access violation tends to be very easy to debug, if you have the code to the Delphi ActiveX library. Open the library in Delphi and go to the Run menu. Under Parameters, select Debugger, and set the Visual Studio EXE you're compiling your VB project under as the Host Application. Close the dialog and hit Run. It should launch Visual Studio. Go to compile your VB project, and when the error occurs, Delphi will drop you into the debugger and it should be obvious from examining the code, the stack and the local variables list what's causing it.
If you don't have the code, then you'll have to settle for providing detailed repro steps to the author of the library and hope they can fix it.
Mason Wheeler
2010-09-21 18:21:14