In computer software standards and documentation, deprecation is the gradual phasing-out of a software or programming language feature. Computer software (or simply software) refers to one or more computer programs held in the storage of a computer for some purpose. ... An alternate rewrite has been has been proposed. ...

A feature or method marked as deprecated is one which is considered obsolete, and whose use is discouraged. The feature still works in the current version of the software, although it may raise error messages as warnings. These serve to alert the user to the fact that the feature may be removed in future releases. An error has different meanings in different domains. ...

Features get marked as deprecated, rather than simply removed, in order to provide backward compatibility for software users. When other programs depend on the deprecated feature, programmers need time to change their code to avoid the feature. In technology (especially computing), backward compatibility has several related but differing meanings: A system is backward compatible if it is compatible with earlier versions of itself, or sometimes other earlier systems, particularly systems it intends to supplant. ...

Programmers or standards-makers may choose to deprecate a feature for any number of reasons. Some common cases are:

• The feature has been replaced by a more powerful, alternate feature. For instance, the Linux kernel contains two filesystem drivers to access Windows file servers -- smbfs and cifsfs. The later cifsfs provides better security, supports more server features, and integrates better with the rest of the kernel. Since the inclusion of cifsfs, smbfs has been deprecated.
• The feature contains a design flaw -- frequently a security flaw -- and so should be avoided; but existing code depends upon it. The C standard function gets() is an example of this. Using this function can introduce a buffer overflow into the program that uses it. However, it cannot be removed as it is part of the C standard, and a compiler which lacks it would be out of conformance. Therefore, compilers raise warnings when it is used.
• The feature is considered extraneous, and will be removed in the future in order to simplify the system as a whole. Early versions of the Web markup language HTML included a FONT element, to allow page designers to specify the font in which text should be displayed. With the release of Cascading Style Sheets and HTML 4.0, the FONT element became extraneous, and detracted from the benefits of noting structural markup in HTML and graphical formatting in CSS. Thus, the FONT element was deprecated in the Transitional HTML 4.0 standard, and eliminated in the Strict variant.
• A future version of the software is planned to make major structural changes, which make it impossible (or impractical) to support older features. For instance, when Apple Computer planned the transition from Mac OS 9 to Mac OS X, it created a subset of the older system's API which would support most programs with minor changes. This became the Carbon library, available in both OS 9 and OS X. Programmers (who were, at the time, chiefly using OS 9) could ensure that their programs would run natively on OS X by using only the API functions in Carbon. Other OS 9 functions were deprecated, and were never supported natively in OS X.

Tux, a penguin, is the official Linux mascot. ... The word kernel has a a variety of meanings in a several fields. ... See Filing system for this term as it is used in libraries and offices In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ... Microsoft Windows is a range of operating environments for personal computers and servers. ... The C Programming Language, Brian Kernighan and Dennis Ritchie, the original edition that served for many years as an informal specification of the language The C programming language is a standardized programming language developed in the early 1970s by Ken Thompson and Dennis Ritchie for use on the UNIX operating... In computer programming, a buffer overflow is an anomalous condition where a program somehow writes data beyond the allocated end of a buffer in memory. ... A diagram of the operation of an ideal compiler. ... Graphic representation of the World Wide Web around Wikipedia The World Wide Web (WWW, W3, or simply Web) is an information space in which the items of interest, referred to as resources, are identified by global identifiers called Uniform Resource Identifiers (URI). ... A specialized markup language using SGML is used to write the electronic version of the Oxford English Dictionary. ... In computing, HyperText Markup Language (HTML) is a markup language designed for the creation of web pages and other information viewable in a browser. ... A font can mean: A member of a typeface family; or digital font - file format that encapsulates a typeface family in a database. ... In computing, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. ... Apple Computer, Inc. ... The Finder in Mac OS 9. ... Mac OS X is the latest version of the Mac OS, the operating system software for Macintosh computers. ... A is a subset of B If X and Y are sets and every element of X is also an element of Y, then we say or write: X is a subset of (or is included in) Y; X ⊆ Y; Y is a superset of (or includes) X; Y ⊇ X... API redirects here. ... Carbon is the codename of Apple Computers APIs for the Macintosh operating system, which permits a good degree of backward compatibility between source code written to run on the classic Mac OS, and the newer Mac OS X. The APIs are published and accessed in the form of C...

Etymology

In mainstream English, the verb "to deprecate" means, simply, "to disapprove of (something)". It derives from the Latin verb deprecari, meaning "to ward off (a disaster) by prayer." Thus, for a standards document to state that a feature is deprecated is a recommendation against using it. Alternately, (and somewhat more dramatically), the writer implores users against using an old, bad feature so that it can be removed. Latin is the language originally spoken in the region around Rome called Latium. ...

It is sometimes confused with the word "depreciate". (Using deprecated programming language features may, nonetheless, cause the value of a program to depreciate: eventually, the features will be removed, and the program will no longer run.) Declining-balance depreciation of a $50,000 asset with $6,500 salvage value over 20 years. ... A programming language or computer language is a standardized communication technique for expressing instructions to a computer. ...