Library (computing): Difference between revisions

Revision as of 08:31, 1 December 2003

Revision as of 02:30, 12 December 2003

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Libraries can be linked dynamically. In [[Microsoft Windows]], those are called '''dynamically linked library''', or '''DLL'''. Conventional libraries are often called static library to distinguish from shared libraries.

A DLL is a [[library (software)|software library]] (often stored in a [[computer file|file]]) consisting of a collection of resources or routines that are available to other programs. A program that wants to use these routines is linked (see [[linker]]) with the DLL at the time it is actually started or later. Oppose this with a [[static library]], the contents of which are copied into the program when the program is compiled and linked.

A program performing the former task is called a [[loader]], while the latter task is accomplished by a [[linker]]. However, to link a program against a DLL, thus making the program request that a particular DLL be loaded when it is started, the linker also needs to look into the DLL to verify that all symbols (routines and variables) used by the program are actually provided by the DLL, thus leaving the impression that ''dynamic'' linking is performed at ''compile time'', while it actually happens at ''run time'' (in most cases, at ''program start time'').