What Is A DLL
What Is A DLL
(Dynamic Link Library)
An executable program module that performs some function. DLLs are widely used in Windows, but they are not launched directly by the user. When needed, they are called for by a running application and are loaded to provide additional functionality.
DLLs can be rather simple, such as providing the ability to display a 3-D border around a dialog box (CTL3DV2.DLL), or as complicated as a full-blown language interpreter such as a Visual Basic runtime module (VBRUN400.DLL).
DLLs are generally written so that their routines are shared by more than one application at the same time (see reentrant code). There are many DLLs that come with Windows that applications depend on (look in your \WINDOWS\SYSTEM folder for the .DLL extension).
Applications may also include their own DLLs, which may be stored in the application folder or in the \WINDOWS\SYSTEM folder.
In the DOS world, there was never a formal way to dynamically link and share routines at runtime. ISRs and TSRs were created for this purpose, but they were not sanctioned by Microsoft and often caused conflict.
Unfortunately, there are still conflicts in the DLL world.
Conceptually, it is as if several people were each baking a cake from a single copy of a recipe on the wall. Everyone looks at the master recipe, but keeps track of their own progress by jotting down the step they are at on their own scratchpad so they can pick up where they left off. The master recipe is never disturbed.
Back To The Top
Bud's CDs FREE MP3s Alphabetical Index Of Everything In This Site