abstract functions in dll

[kim78]

Hello,

I have a dll that opens a UDP port to a server and handle all the communication.

I have a function that is triggered once I am getting a data from the UDP port. This function is abstract, I have only definition of it in the dll, but the implementation is outside, in the main application.

If I am using a lib instead of a dll, everything is fine. But if I am using a released dll, I can't compile it at all..

I am getting an error

error: Undefined symbol '_UDPChatCallback' referenced in "c:\CVI\Drivers\AlTerm\cvibuild.alterm\Debug\alterm.obj".

[rolfk]

Show your code, but most likely this is not an "abstract function" which doesn't exist in standard C at all, but rather a callback function and your application is supposed to implement that function in order for that library to call back into your program and inform you of the state it is in while doing its work.

[ZKami]

Hi Kim78,

You could also take a look at this document which covers the causes of this kind of error:  https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019KrgSAE&l=en-US