throwing exceptions from a labview dll

[GYF]

I have created a vi in labview 8.2 and compiled the project with this single vi into a dll.  Then I have a C# code, which calls the vi as a function call.  The simple example I have created works fine.  At this point I would like to extend my example to explore error handling and callback functions.  

1.  Is it possible to "throw" an exception from a Labview VI, that was compiled into the DLL, and catch it in my C# code, which makes the call?  ...How can I do this? 

2.  Is it possible to pass a "callback" pointer to my Labview DLL function, so that when I call the function from C#, I can have the Labview DLL function execute my "callback" function? 

3.  Where can I read about the limitations of interfacing from C# to Labview DLLs (I could not find the answers to my questions in the Help files)?

Thanks,

Gene Fridman

[Wiebe@CARYA]

Gene,


"1.Is it possible to "throw" an exception from a Labview VI, that was compiled into the DLL, and catch it in my C# code, which makes the call? ...How can I do this?"


Not with native LabVIEW (perhaps if you misuse one of the exported functions, but it will be experimental). But you can make a c++ or assembler dll with a devide by zero in it, or an int 2 or something to trigger the exeption. It just might work...


"2. Is it possible to pass a "callback" pointer to my Labview DLL function, so that when I call the function from C#, I can have the Labview DLL function execute my "callback" function?"


If you want the LabVIEW function to act as the callback, you can use LoadLibrary and GetProcAddress to get a pointer to the LabVIEW dll function.


If you want the C# function to be called from LabVIEW, you'll have to make a export function that makes the call.


"3.Where can I read about the limitations of interfacing from C# to Labview DLLs (I could not find the answers to my questions in the Help files)?"


No idea about that. I guess this forum or LAVA (google "LAVA LabVIEW") would be your best bet.


Regards,


Wiebe.