Re: beginner: assertion error on class export from dll

"Frank Hickman [MVP]" <>
Mon, 19 Jun 2006 23:29:40 -0400
".rhavin grobert" <> wrote in message

Frank Hickman [MVP] asked:

What is it your attempting to accomplish?

i have a couple of files of my own i type and i want to write a dll
that exports a class with some methods for loading / saving them and
manipulating the loaded data. so i want the dll to be loadable and to
export something like

DllFileObjectType myFileObject = DllExpFuncForNewObject();

myFileObject.Filename = "some_path\\"; // typedef'd to

myFileObject.LoadFromFile(); // a dll-object-method


If your DLL is only going to be used by C++, probably not though, I would
suggest writing a DLL which exports the class without the API type calls.
This will create an import library much like the MFC libraries which your
applications can link too and allow the application to create and
instantiate within itself. If on the other hand you want to also allow
other development environments use the DLL, you can use an init function
that creates the object within the DLL, returns a handle to it so that you
can manipulate the functions within the object. You could also simply
export individual class functions but you would need to deal with the C++
name mangling in this case.

In the first case you could create your class within the DLL and provide a
header to allow your application to know about the class. Then link to the
import library in your application. You can use this method just as if the
DLL class was contained within the application code.

Frank Hickman
Microsoft MVP
NobleSoft, Inc.
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