What are DLL’s and which are the different types of DLL’s ?
Dynamic link libraries (also called as DLL’s) are a very important part of windows. Most of the files associated with windows are either executables or DLL’s.
Unlike executable which can be directly invokes, a DLL cannot be invoked directly. Instead a DLL is a set of files containing functions that can be called by other programs or other DLL’s to get the job done.
Dynamic linking means the process that Windows uses to link a function call of one module to the actual function in the DLL. Linking is of two types: static and dynamic linking.
Static Linking happens during program development time while dynamic linking happens at run time. One can create a DLL of resource only as well. DLL usually have an extension .DLL which is loaded by windows automatically when required however one can load DLL using LoadLibrary or LoadLibraryEx calls as well.
The two types of DLL which one can make with MFC are:
- Extension DLL: These DLL’s exposes variables and functions to the client application. It can expose C++ functions and C++ classes to be used in your application.
- Regular DLL: MFC extension DLL’s can be used only with MFC applications. If you want a dll to be used by a wider range of applications then use a regular DLL.