Editing Library (computing) (section)

==File naming==
===Unix-like===
On most modern [[Unix-like]] systems, library files are stored in directories such as <code>/lib</code>, <code>/usr/lib</code> and <code>/usr/local/lib</code>. A filename typically starts with <code>lib</code>, and ends with <code>.a</code> for a static library ([[Ar (file format)|archive]]) or <code>.so</code> for a shared object (dynamically linked library). For example, <code>libfoo.a</code> and <code>libfoo.so</code>.

Often, [[symbolic link]] files are used to manage versioning of a library by providing a link file named without a version that links to a file named with a version. For example, <code>libfoo.so.2</code> might be version 2 of library ''foo'' and a link file named <code>libfoo.so</code> provides a version independent name to that file that programs link to. The link file could be changed to a refer to a version 3 (<code>libfoo.so.3</code>) such that consuming programs will then use version 3 without having to change the program.

Files with extension <code>.la</code> are [[libtool]] archives; not usable by the system.

===macOS===
{{see also|Dynamic linker#macOS and iOS}}
The [[macOS]] system inherits static library conventions from [[BSD]], with the library stored in a <code>.a</code> file. It uses either <code>.so</code> or <code>.dylib</code> for dynamic libraries. Most libraries in macOS, however, consist of "frameworks", placed inside special directories called "[[Bundle (macOS)|bundles]]" which wrap the library's required files and metadata. For example, a framework called <code>Abc</code> would be implemented in a bundle called <code>Abc.framework</code>, with <code>Abc.framework/Abc</code> being either the dynamically linked library file or a symlink to the dynamically linked library file in <code>Abc.framework/Versions/Current/Abc</code>.

===Windows===
Often, a [[Microsoft Windows|Windows]] [[dynamic-link library]] (DLL) has the file extension <code>.dll</code>,<ref>
{{cite book
 |last1            = Bresnahan
 |first1           = Christine
 |last2            = Blum
 |first2           = Richard
 |title            = LPIC-1 Linux Professional Institute Certification Study Guide: Exam 101-400 and Exam 102-400
 |url              = https://books.google.com/books?id=jf3zBgAAQBAJ
 |publisher        = John Wiley & Sons
 |publication-date = 2015
 |page             = 82
 |isbn             = 9781119021186
 |access-date       = 2015-09-03
 |quote            = Linux shared libraries are similar to the dynamic link libraries (DLLs) of Windows. Windows DLLs are usually identified by <code>.dll</code> filename extensions.
 |date             = 2015-04-27
 |url-status          = live
 |archive-url       = https://web.archive.org/web/20150924234210/https://books.google.com/books?id=jf3zBgAAQBAJ
 |archive-date      = 24 September 2015
}}
</ref> although sometimes different extensions are used to indicate general content, e.g. <code>.ocx</code> for a [[Object Linking and Embedding|OLE]] library. 

A <code>.lib</code> file can be either a static library or contain the information needed to build an application that consumes the associated DLL. In the latter case, the associated DLL file must be present at runtime.