Dynamic-Link Libraries

基本介紹

• 中文名：動態程式庫
• 外文名：Dynamic-Link Libraries
• 縮寫：DLL
• 內涵：是一種包含函式和數據的模組

概念

動態程式庫(DLL)是一種包含函式和數據的模組。一個DLL可以在運行時被另一個模組(.exe.或者.dll)載入。當一個dll被載入時，它將被映射到調用者進程的地址空間中。

一個dll可以定義兩種類型的函式：導出函式和內部函式。導出函式可以被其他模組調用。內部函式只能由定義它的dll在內部使用。雖然dll可以導出數據，但他的數據往往是由他自己的函式所使用。Dll提供給應用程式一種模組化方案，使得程式功能的更新和重用更加容易。也可以減少記憶體開銷，在多個應用程式，相同的時間使用相同的功能時。因為這些程式可以共享Dll中的代碼，儘管每個應用程式有自己的數據副本。

Windows應用程式編程接口（API）就是通過一系列的動態程式庫的方式實現的，因此所有使用Windows API的進程都可以使用動態連結。

英文翻譯

Dynamic-link libraries (DLL) are modules that contain functions and data. A DLL is loaded at run time by its calling modules (.exe or .dll). When a DLL is loaded, it is mapped into the address space of the calling process.

A DLL can define two kinds of functions: exported and internal. The exported functions can be called by other modules. Internal functions can only be called from within the DLL where they are defined. Although a DLL can export data, its data is usually only used by its functions.

DLLs provide a way to modularize applications so that functionality can be updated and reused more easily. They also help reduce memory overhead when several applications use the same functionality at the same time, because although each application gets its own copy of the data, they can share the code.

The Windows application programming interface (API) is implemented as a set of dynamic-link libraries, so any process that uses the Windows API uses dynamic linking.