What is the difference between dllexport and dllimport?

visual-c++ dll import export
1800 INFORMATION picture 1800 INFORMATION · Sep 12, 2008 · Viewed 30.9k times · Source

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

Shog9 picture Shog9 · Sep 12, 2008

__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

Related questions

How do I set the path to a DLL file in Visual Studio?

I developed an application that depends on a DLL file. When I debug my application, the applicationwould complain that: "This application has failed to start because xxx.dll was not found." So I have to copy the DLL file into …

Read More
Where to download Microsoft Visual c++ 2003 redistributable

I have an old dll that uses the Microsoft Visual C++ 2003 (7.1) run time package. Unfortunately I don't have that DLL around anymore. Short of reinstalling VS2003, is there another way to get the run time redistributable dll?

Read More
Exporting functions from a DLL with dllexport

I'd like a simple example of exporting a function from a C++ Windows DLL. I'd like to see the header, the .cpp file, and the .def file (if absolutely required). I'd like the exported name to be undecorated. I'd like …

Read More