Static library and dynamic library distinction in C++?

Question

Hello friend, Static library(.lib) and dynamic library(.dll) distinction in C++? Static libraries have what use?What is the import library? Import library have what use? Thanks in advance.

Vulpes · Answer

In the case of a static library (.lib file), the linker looks for all the functions which your application references and merges the code for those functions into the compiled application itself. In contrast, a dynamic link library (.dll) remains separate from the application. The latter just contains sufficient information to enable it to call the appropriate .dll functions at runtime. The advantages of static libraries are: 1. You only need to distribute your application - you don't need to distribute the .lib file as well. 2. As the .lib file is part of your application, versioning is not a problem - you always have the correct version built in. The disadvantages are : 1. If you use the static library in more than one application, you're wasting disk space because each application contains a copy of the library. 2. If you want to use an updated version of the .lib file, then you have to recompile and redistribute your application. As .dlls are not part of your application, they have to be loaded at runtime and the appropriate functions then need to be referenced. An 'import library' is a small .lib file which automates this process and which usually has the same name as the .dll. The import library is linked into your application at compile time in the usual way and you can then call the .dll functions as though they'd been statically linked.

Vulpes · Answer

The problem is that extern "C" isn't supported by the C compiler because it's not needed. It's only supported by the C++ compiler. So, if you change Ken.c to this, then it should compile and run OK: // Ken.c #include #pragma comment(lib,"Vulpes.lib") __declspec(dllimport) void myFunction(); int main(){ myFunction(); printf("And hello also from Ken!"); return 0; }

Ken H · Answer

Thank for you Vulpes. :) I created a dll file and automatically generate the .lib files. They are: Vulpes.dll Vulpes.lib They code are: // Vulpes.c #include __declspec(dllexport) void myFunction() { printf ("Hello Vulpes!
"); } Now I try to use dllimport command, but compile error has occurred. Error tops: Ken.c (4): error C2059: syntax error: "string" codes: // Ken.c #include #pragma comment(lib,"Vulpes.lib") extern "C" __declspec(dllimport) void myFunction(); int main(){ myFunction(); printf("And hello also from Ken!"); return 0; }

Static library and dynamic library distinction in C++?

Answers (3)