> In a vi I call a dll compiled in C++. It seems that the function which
> has been called does what it is supposed to do, only it returns error
> message:"An exception occured within the external code called by a
> Call Library Node" and then the execution of the vi is stopped. I have
> no idea what an "exception" means. Is it the problem in the external
> code really, or in a way how I call the function?
It could mean either. What this means is that LV has a TRY block around
the DLL call. The DLL threw an exception of some kind, and the
TRY/CATCH prevented the LV application from crashing. If you have the
source code to the DLL, wrap the entrypoint with your own TRY/CATCH and
place a breakpoint at the CATCH point or step through your code.
Examples of
things that can cause an exception are division by zero,
dereferencing a bad pointer, calling new with a very large number.
These runtime errors are sometimes due to bad configuration of the node
where the parameters from the diagram are being handed to the DLL.
Again, stopping just inside of the DLL and inspecting the parameters is
always a good technique for debugging this sort of problem.
Greg McKaskle
