What is the difference between dllexport and dllimport?

Question

I'm just looking for a simple, concise explanation of the difference between these two. MSDN doesn't go into a hell of a lot of detail here.

Answer 1

__declspec( dllexport ) - The class or function so tagged will be exported from the DLL it is built in. If you're building a DLL and you want an API, you'll need to use this or a separate .DEF file that defines the exports (MSDN). This is handy because it keeps the definition in one place, but the .DEF file provides more options.

__declspec( dllimport ) - The class or function so tagged will be imported from a DLL. This is not actually required - you need an import library anyway to make the linker happy. But when properly marked with dllimport, the compiler and linker have enough information to optimize the call; without it, you get normal static linking to a stub function in the import library, which adds unnecessary indirection. ONT1 ONT2

Answer 2

• __declspec(dllexport) tells the linker that you want this object to be made available for other DLL's to import. It is used when creating a DLL that others can link to.

• __declspec(dllimport) imports the implementation from a DLL so your application can use it.

I'm only a novice C/C++ developer, so perhaps someone's got a better explanation than I.