Benefits of Using DLLs:

The dynamic linking has the following advantages which are as shown below:

• It saves memory and decreases the swapping. Many processes can use a single DLL concurrently, sharing a single copy of the DLL in the memory. In contrast, the Windows should load a copy of the library code into the memory for each application which is built with a static link library.
• The DLL saves the disk space. Many applications can share a single copy of the DLL on the disk. In contrast, each application built with a static link library has the library code linked into its executable image as a individual copy.
• Upgrades to the DLL are much easier. When the functions in a DLL change, the applications which use them do not required be recompiling or re-linking as long as the functions arguments and return values do not change. In difference, the statically linked object code needs that the application be re-linked when the functions changes.
• It Supports multi language programs. The Programs written in various programming languages can call the same DLL function as long as the programs follow the functions calling convention. The programs and the DLL function should be compatible in the following ways: the order in which the function expects its arguments to be pushed into the stack, whether the function or the application is answerable for cleaning up the stack, and whether any of the arguments are passed in the registers.
• ?It provides a mechanism to expand the MFC library classes. You can derive the classes from the existing MFC classes and place them in an MFC extension DLL for use by the MFC applications.
• It eases the creation of the international versions. By placing resources in the DLL, it is much easier to create international versions of an application. You can locate the strings for each language version of your application in individual resource DLL, and have the various language versions load the suitable resources.
• A potential demerit to using DLLs is that the application is not self-contained; it depends on the existence of an individual DLL module.