help!! callback in dll....

i.m C,C++ beginner user.
how make callback fuction in the DLL?
and how call "callback fuction" in the host program?
sorry about my basic question....
help....

:)

Quote:

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Originally posted by kimcs
i.m C,C++ beginner user.
how make callback fuction in the DLL?
and how call "callback fuction" in the host program?
sorry about my basic question....
help....

:)

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Callback function?
DLL?
These are "basic" questions from a beginner user? Quite advanced if you ask me.

I don't remember exactly how the callback function I used works, but MSDN may have your answer.

I think what you are trying to say is "export" functions.

Well, since this is Windows specific just declare your functions with __declspec(export) and include the .lib in your host program.

Are you asking about DLLMain()? I think you need to clarify the situation.

>how make callback fuction in the DLL?
>and how call "callback fuction" in the host program?

Not easy stuff for a beginner, but here's an explanation.

Normally an application calls functions provided by a DLL. Sometimes, however, it handy to have the DLL call a function in the application. A typical example of when this may be done, is when the application may call a routine in DLL which takes a long time to complete. During the workings of this function, it may periodically call a 'callback' function in the application to provide it with progress information and allow it to terminate the routine early (if the user clicks abort). To implemet a callback, you normally have to pass the DLL a pointer to your callback function.