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<!DOCTYPE html> <html lang="en"> <head> <title>Ada from FOLDOC</title> <meta http-equiv="Content-Security-Policy" content="default-src 'unsafe-inline' http: https:"> <meta name="verify-v1" content="siAI0ZOMn41hao0E/T76D1I2L3MtFjzE48P3ctCjRNU="> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <meta name="msapplication-TileColor" content="#da532c"> <meta name="theme-color" content="#ffffff"> <meta name="google-translate-customization" content="828219db36930e1e-c51d915bf2ea717c-g9b503f9a85d5b5a7-a">  <script src="https://www.googletagmanager.com/gtag/js?id=UA-9715943-1"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'UA-9715943-1'); </script>  <link href="//fonts.googleapis.com/css?family=Duru+Sans%7CBelgrano%7CInconsolata%7CAlef%7CArmata" rel="stylesheet" type="text/css"> <link rel="stylesheet" type="text/css" href="/css/layout.css?2">  <link rel="apple-touch-icon" sizes="152x152" href="/im/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="/im/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="/im/favicon-16x16.png"> <link rel="manifest" href="/im/site.webmanifest"> <link rel="mask-icon" href="/im/safari-pinned-tab.svg" color="#5bbad5"> <link rel="canonical" href="https://foldoc.org/Ada"> <link rel="alternate" type="application/rss+xml" title="FOLDOC" href="/rss.xml"> <link rel="search" title="FOLDOC" type="application/opensearchdescription+xml" href="//foldoc.org/search.xml">  <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-5521724329338202" crossorigin="anonymous"></script>  </head> <body> <div id="fb-root"></div> <script> (function (d, s, id) { var js, fjs = d.getElementsByTagName(s)[0]; if (d.getElementById(id)) return; js = d.createElement(s); js.id = id; js.src = "//connect.facebook.net/en_GB/all.js#xfbml=1"; fjs.parentNode.insertBefore(js, fjs); }(document, 'script', 'facebook-jssdk')); </script> <div id="container"> <div id="left"> <a href="/"> <img src="/foldoc.gif" width="300" height="98" alt="Free On-line Dictionary of Computing" class="logo"> </a> <div id="nav"> <a href="/contents.html" class="button">Contents</a> <a href="/help.html" class="button">Help</a> <a href="/random-entry" class="button">Random</a> </div> <form action="/"> <input type="text" name="query" id="query" autofocus="autofocus"> <input type="submit" name="action" value="Search" class="button"> </form> <div id="content"> <h2>Ada</h2> <p></p> <p><<i><a href="contents/language.html">language</a></i>></p> <p> (After <a href="/Ada+Lovelace">Ada Lovelace</a>) A <a href="/Pascal">Pascal</a>-descended language, designed by Jean Ichbiah's team at <a href="/CII+Honeywell">CII Honeywell</a> in 1979, made mandatory for Department of Defense software projects by the Pentagon. The original language was standardised as "Ada 83", the latest is "<a href="/Ada+95">Ada 95</a>". <p></p> Ada is a large, complex, <a href="/block-structured">block-structured</a> language aimed primarily at <a href="/embedded">embedded</a> applications. It has facilities for <a href="/real-time">real-time</a> response, <a href="/concurrency">concurrency</a>, hardware access and reliable run-time error handling. In support of large-scale <a href="/software+engineering">software engineering</a>, it emphasises <a href="/strong+typing">strong typing</a>, <a href="/data+abstraction">data abstraction</a> and <a href="/encapsulation">encapsulation</a>. The type system uses <a href="/name+equivalence">name equivalence</a> and includes both <a href="/subtypes">subtypes</a> and <a href="/derived+types">derived types</a>. Both fixed and <a href="/floating-point">floating-point</a> numerical types are supported. <p></p> <a href="/Control+flow">Control flow</a> is fully bracketed: if-then-elsif-end if, case-is-when-end case, loop-exit-end loop, goto. Subprogram parameters are in, out, or inout. Variables imported from other packages may be hidden or directly visible. Operators may be <a href="/overloaded">overloaded</a> and so may <a href="/enumeration">enumeration</a> literals. There are user-defined <a href="/exceptions">exceptions</a> and <a href="/exception+handlers">exception handlers</a>. <p></p> An Ada program consists of a set of packages encapsulating data objects and their related operations. A package has a separately compilable body and interface. Ada permits <a href="/generic+packages">generic packages</a> and subroutines, possibly parametrised. <p></p> Ada support <a href="/single+inheritance">single inheritance</a>, using "tagged types" which are types that can be extended via <a href="/inheritance">inheritance</a>. <p></p> Ada programming places a heavy emphasis on <a href="/multitasking">multitasking</a>. Tasks are synchronised by the <a href="/rendezvous">rendezvous</a>, in which a task waits for one of its subroutines to be executed by another. The conditional entry makes it possible for a task to test whether an entry is ready. The selective wait waits for either of two entries or waits for a limited time. <p></p> Ada is often criticised, especially for its size and complexity, and this is attributed to its having been designed by committee. In fact, both Ada 83 and Ada 95 were designed by small design teams to be internally consistent and tightly integrated. By contrast, two possible competitors, <a href="/Fortran+90">Fortran 90</a> and <a href="/C%2b%2b">C++</a> have both become products designed by large and disparate volunteer committees. <p></p> See also <a href="/Ada/Ed">Ada/Ed</a>, <a href="/Toy/Ada">Toy/Ada</a>. <p></p> <em><a href="http://lglwww.epfl.ch/Ada/">Home of the Brave Ada Programmers</a></em>. <em><a href="http://lglwww.epfl.ch/Ada/FAQ/">Ada FAQs</a></em> (hypertext), <em><a href="ftp://lglftp.epfl.ch/pub/Ada/FAQ">text only</a></em>. <p></p> <em><a href="http://wuarchive.wustl.edu/languages/ada/">http://wuarchive.wustl.edu/languages/ada/</a></em>, <em><a href="ftp://ajpo.sei.cmu.edu/">ftp://ajpo.sei.cmu.edu/</a></em>, <em><a href="ftp://stars.rosslyn.unisys.com/pub/ACE_8.0">ftp://stars.rosslyn.unisys.com/pub/ACE_8.0</a></em>. <p></p> E-mail: <em><a href="/cdn-cgi/l/email-protection#a1c0c5c0c8cfc7cee1c0cbd1ce8fd2c4c88fc2ccd48fc4c5d4"><<span class="__cf_email__" data-cfemail="3a5b5e5b53545c557a5b504a5514495f531459574f145f5e4f">[email protected]</span>></a></em>. <p></p> <a href="/Usenet">Usenet</a> newsgroup: <a href="https://groups.google.com/group/comp.lang.ada">comp.lang.ada</a>. <p></p> <em><a href="ftp://primost.cs.wisc.edu/">An Ada grammar</a></em> including a lex scanner and yacc parser is available. E-mail: <em><a href="/cdn-cgi/l/email-protection#85e8e4f6f1ece6eae9c5e1f0e8e4f6abf7f0f1e2e0f7f6abe0e1f0"><<span class="__cf_email__" data-cfemail="e18c80929588828e8da185948c8092cf93949586849392cf848594">[email protected]</span>></a></em>. <p></p> <em><a href="ftp://wsmr-simtel20.army.mil/PD2:<ADA.EXTERNAL-TOOLS>GRAM2.SRC">Another yacc grammar and parser for Ada by Herman Fischer</a></em>. <p></p> An <a href="/LR+parser">LR parser</a> and <a href="/pretty-printer">pretty-printer</a> for <a href="/Ada">Ada</a> from NASA is available from the <a href="/Ada+Software+Repository">Ada Software Repository</a>. <p></p> <a href="/Adamakegen">Adamakegen</a> generates <a href="/makefiles">makefiles</a> for <a href="/Ada">Ada</a> programs. <p></p> ["Reference Manual for the Ada Programming Language", ANSI/MIL STD 1815A, US DoD (Jan 1983)]. Earlier draft versions appeared in July 1980 and July 1982. ISO 1987. <p></p> [<a href="/Jargon+File">Jargon File</a>] <p></p> <p class="updated">Last updated: <a href="/new.html">2000-08-12</a></p> <p></p> <p class="vertical-space"></p><h3>Nearby terms:</h3> <p class="neighbours"> <a href="/actuator/health">actuator/health</a> &diams; <a href="/Actus">Actus</a> &diams; <a href="/AD">AD</a> &diams; <a href="/ad">ad</a> &diams; <b><a href="/Ada">Ada</a></b> &diams; <a href="/Ada%2b%2b">Ada++</a> &diams; <a href="/Ada+83">Ada 83</a> &diams; <a href="/Ada+95">Ada 95</a> &diams; <a href="/Ada+9X">Ada 9X</a> </p> <p> Try this search on <a href="https://www.wikipedia.org/wiki/Special:Search?search=Ada">Wikipedia</a>, <a href="https://www.wiktionary.org/wiki/Ada">Wiktionary</a>, <a href="https://www.google.com/search?q=define:Ada">Google</a>, <a href="https://www.onelook.com/?w=Ada">OneLook</a>. </p> <p class="vertical-space"></p> <hr> <div></div> <hr>  <div id="HCB_comment_box">Loading</div> <link rel="stylesheet" type="text/css" href="//www.htmlcommentbox.com/static/skins/bootstrap/twitter-bootstrap.css?v=0"> <script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script><script language="javascript" id="hcb"> hcb_user = { PAGE: 'https://foldoc.org/Ada', comments_header: ' ', no_comments_msg: ' ', err_comment_empty: 'Your comment was not posted because it was empty!', rss: '', }; var s = document.createElement("script"); s.setAttribute("type", "text/javascript"); s.setAttribute("src", "//www.htmlcommentbox.com/jread?page=" + escape(hcb_user.PAGE).replace(/\+/g, "%2B") + "&mod=%241%24wq1rdBcg%24.0y2uzvjA2bsnhzpXVq9F." + "&opts=17374&num=10"); // No e-mail field: 16846 if (typeof s != "undefined") document.getElementsByTagName("head")[0].appendChild(s); </script> <script> setTimeout(function () { document.getElementById('hcb_form_content').rows = 1 }, 1000); </script> <hr>  </div>  </div>  <div id="right"> <div id="google_translate_element"> <script> function googleTranslateElementInit() { new google.translate.TranslateElement({ pageLanguage: 'en' }, 'google_translate_element'); } </script> <script src="https://translate.google.com/translate_a/element.js?cb=googleTranslateElementInit"></script> </div> <p><br></p> <hr> <div id="social"> <div class="fb-like" data-href="http://foldoc.org/" data-layout="button_count" data-action="like" data-show-faces="false" data-share="true"> </div> <a href="https://twitter.com/share" class="twitter-share-button" data-via="foldoc"> Tweet </a> <script> if (!document.getElementById('twitter-wjs')) { var fjs = document.getElementsByTagName('script')[0], js = document.createElement('script'); js.id = 'twitter-wjs'; js.src = 'https://platform.twitter.com/widgets.js'; fjs.parentNode.insertBefore(js, fjs); } </script> </div> <hr> <div> <p></p> </div> <p> <a href="/rss.xml"> <img src="/orangerss.gif" width="14" height="14" alt="RSS feed of new items"> </a>   <a href="/new.html">Recent Updates</a>     |     <a href="/missing.html">Missing Terms</a> </p> <p>Updated: Sat, 05 Apr 2025 21:25:49 GMT</p> <p>15282 entries</p> <p><em><a href="/Free+On-line+Dictionary">Copyright Denis Howe 1985</a></em></p> </div>  </div>   <script type="text/javascript"> window._qevents = window._qevents || []; (function() { var elem = document.createElement('script'); elem.src = 'https://secure.quantserve.com/quant.js'; elem.async = true; elem.type = 'text/javascript'; var scpt = document.getElementsByTagName('script')[0]; scpt.parentNode.insertBefore(elem, scpt); })(); window._qevents.push({ qacct: 'p-48Rosdvs3EiOc', uid: '__INSERT_EMAIL_HERE__' }); </script> <noscript> <div style="display:none;"> <img src="https//pixel.quantserve.com/pixel/p-48Rosdvs3EiOc.gif" border="0" height="1" width="1" alt="Quantcast"/> </div> </noscript>  </body> </html>