DLL (Dynamic-Link Library) – a shared library in a Microsoft Windows environment that stores implementations of various program subroutines or program resources. The subroutines and resources contained in the DLL can be used directly or indirectly (via a different DLL) by any executable file, the DLL itself is not a stand-alone program.
Dynamic library functions (DLL) can be simultaneously (at the same time) imported by many programs (hence the term: shared library), thanks to this the operational memory is less loaded. DLLs can be imported statically or dynamically. Unlike static libraries that are linked to the program at the time of its consolidation, dynamically imported DLLs are a separate part of the program and their modification does not require re-consolidation, however a problem with the library (no imported functions or problem loading the library) completely prevents program. Dynamically imported libraries are loaded into the operating memory only at the moment defined by the programmer (usually when they are actually needed) – hence the term: dynamically linked library – so DLL files are often used as plug-ins in various programs.
In Microsoft Windows, DLLs have the extension .dll, .ocx (when the library is an ActiveX control), .cpl (when the library is an extension of the Control Panel), .drv (when it is driver), and can be used in programs written in different languages for the Windows platform, including in Visual Basic, C / C ++ / C #, Object Pascal (Delphi) or assembler.
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