121
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Your task is to create the shortest infinite loop!

The point of this challenge is to create an infinite loop producing no output, unlike its possible duplicate. The reason to this is because the code might be shorter if no output is given.

Rules

  • Each submission must be a full program.
  • You must create the shortest infinite loop.
  • Even if your program runs out of memory eventually, it is still accepted as long as it is running the whole time from the start to when it runs out of memory. Also when it runs out of memory, it should still not print anything to STDERR.
  • The program must take no input (however, reading from a file is allowed), and should not print anything to STDOUT. Output to a file is also forbidden.
  • The program must not write anything to STDERR.
  • Feel free to use a language (or language version) even if it's newer than this challenge. -Note that there must be an interpreter so the submission can be tested. It is allowed (and even encouraged) to write this interpreter yourself for a previously unimplemented language. :D
  • Submissions are scored in bytes, in an appropriate (pre-existing) encoding, usually (but not necessarily) UTF-8. Some languages, like Folders, are a bit tricky to score - if in doubt, please ask on Meta.
  • This is not about finding the language with the shortest infinite loop program. This is about finding the shortest infinite loop program in every language. Therefore, I will not accept an answer.
  • If your language of choice is a trivial variant of another (potentially more popular) language which already has an answer (think BASIC or SQL dialects, Unix shells or trivial Brainf**k-derivatives like Alphuck), consider adding a note to the existing answer that the same or a very similar solution is also the shortest in the other language.
  • There should be a website such as Wikipedia, Esolangs, or GitHub for the language. For example, if the language is CJam, then one could link to the site in the header like #[CJam](http://sourceforge.net/p/cjam/wiki/Home/), X bytes.
  • Standard loopholes are not allowed.

(I have taken some of these rules from Martin Büttner's "Hello World" challenge)


Please feel free to post in the comments to tell me how this challenge could be improved.

Catalogue

This is a Stack Snippet which generates both an alphabetical catalogue of the used languages, and an overall leaderboard. To make sure your answer shows up, please start it with this Markdown header:

# Language name, X bytes

Obviously replacing Language name and X bytes with the proper items. If you want to link to the languages' website, use this template, as posted above:

#[Language name](http://link.to/the/language), X bytes

Now, finally, here's the snippet: (Try pressing "Full page" for a better view.)

var QUESTION_ID=59347;var ANSWER_FILTER="!t)IWYnsLAZle2tQ3KqrVveCRJfxcRLe";var COMMENT_FILTER="!)Q2B_A2kjfAiU78X(md6BoYk";var OVERRIDE_USER=41805;var answers=[],answers_hash,answer_ids,answer_page=1,more_answers=true,comment_page;function answersUrl(index){return"//api.stackexchange.com/2.2/questions/"+QUESTION_ID+"/answers?page="+index+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+ANSWER_FILTER}function commentUrl(index,answers){return"//api.stackexchange.com/2.2/answers/"+answers.join(';')+"/comments?page="+index+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+COMMENT_FILTER}function getAnswers(){jQuery.ajax({url:answersUrl(answer_page++),method:"get",dataType:"jsonp",crossDomain:true,success:function(data){answers.push.apply(answers,data.items);answers_hash=[];answer_ids=[];data.items.forEach(function(a){a.comments=[];var id=+a.share_link.match(/\d+/);answer_ids.push(id);answers_hash[id]=a});if(!data.has_more)more_answers=false;comment_page=1;getComments()}})}function getComments(){jQuery.ajax({url:commentUrl(comment_page++,answer_ids),method:"get",dataType:"jsonp",crossDomain:true,success:function(data){data.items.forEach(function(c){if(c.owner.user_id===OVERRIDE_USER)answers_hash[c.post_id].comments.push(c)});if(data.has_more)getComments();else if(more_answers)getAnswers();else process()}})}getAnswers();var SCORE_REG=/<h\d>\s*([^\n,<]*(?:<(?:[^\n>]*>[^\n<]*<\/[^\n>]*>)[^\n,<]*)*),.*?(\d+)(?=[^\n\d<>]*(?:<(?:s>[^\n<>]*<\/s>|[^\n<>]+>)[^\n\d<>]*)*<\/h\d>)/;var OVERRIDE_REG=/^Override\s*header:\s*/i;function getAuthorName(a){return a.owner.display_name}function process(){var valid=[];answers.forEach(function(a){var body=a.body;a.comments.forEach(function(c){if(OVERRIDE_REG.test(c.body))body='<h1>'+c.body.replace(OVERRIDE_REG,'')+'</h1>'});var match=body.match(SCORE_REG);if(match)valid.push({user:getAuthorName(a),size:+match[2],language:match[1],link:a.share_link,});else console.log(body)});valid.sort(function(a,b){var aB=a.size,bB=b.size;return aB-bB});var languages={};var place=1;var lastSize=null;var lastPlace=1;valid.forEach(function(a){if(a.size!=lastSize)lastPlace=place;lastSize=a.size;++place;var answer=jQuery("#answer-template").html();answer=answer.replace("{{PLACE}}",lastPlace+".").replace("{{NAME}}",a.user).replace("{{LANGUAGE}}",a.language).replace("{{SIZE}}",a.size).replace("{{LINK}}",a.link);answer=jQuery(answer);jQuery("#answers").append(answer);var lang=a.language;lang=jQuery('<a>'+lang+'</a>').text();languages[lang]=languages[lang]||{lang:a.language,lang_raw:lang,user:a.user,size:a.size,link:a.link}});var langs=[];for(var lang in languages)if(languages.hasOwnProperty(lang))langs.push(languages[lang]);langs.sort(function(a,b){if(a.lang_raw.toLowerCase()>b.lang_raw.toLowerCase())return 1;if(a.lang_raw.toLowerCase()<b.lang_raw.toLowerCase())return-1;return 0});for(var i=0;i<langs.length;++i){var language=jQuery("#language-template").html();var lang=langs[i];language=language.replace("{{LANGUAGE}}",lang.lang).replace("{{NAME}}",lang.user).replace("{{SIZE}}",lang.size).replace("{{LINK}}",lang.link);language=jQuery(language);jQuery("#languages").append(language)}}
body{text-align:left!important}#answer-list{padding:10px;width:500px;float:left}#language-list{padding:10px;padding-right:40px;width:500px;float:left}table thead{font-weight:700}table td{padding:5px}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b"> <div id="language-list"> <h2>Shortest Solution by Language</h2> <table class="language-list"> <thead> <tr><td>Language</td><td>User</td><td>Score</td></tr> </thead> <tbody id="languages"> </tbody> </table> </div> <div id="answer-list"> <h2>Leaderboard</h2> <table class="answer-list"> <thead> <tr><td></td><td>Author</td><td>Language</td><td>Size</td></tr> </thead> <tbody id="answers"> </tbody> </table> </div> <table style="display: none"> <tbody id="answer-template"> <tr><td>{{PLACE}}</td><td>{{NAME}}</td><td>{{LANGUAGE}}</td><td>{{SIZE}}</td><td><a href="{{LINK}}">Link</a></td></tr> </tbody> </table> <table style="display: none"> <tbody id="language-template"> <tr><td>{{LANGUAGE}}</td><td>{{NAME}}</td><td>{{SIZE}}</td><td><a href="{{LINK}}">Link</a></td></tr> </tbody> </table>

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  • 41
    \$\begingroup\$ I've got to start posting programs with a negative byte count to beat all these empty files! \$\endgroup\$ – CJ Dennis Oct 3 '15 at 4:32
  • 3
    \$\begingroup\$ This challenge is interesting because it brings out lots of 0 byte languages (some of which are NOT esolangs). FWIW, most declarative languages have an implicit infinite loop because declarative languages don't have loops in their syntax (they assume they're running in an infinite loop). Ladder diagrams are perhaps among the oldest such languages. Then you have the Instruction Language (IL), a sort of assembly for PLCs that also assume an infinite loop. ILs, like assembly are different between manufacturers \$\endgroup\$ – slebetman Oct 5 '15 at 9:36
  • \$\begingroup\$ Are programs that read and execute their own source code allowed, or does file I/O break the "must take no input" rule? \$\endgroup\$ – ThisSuitIsBlackNot Oct 6 '15 at 13:05
  • 1
    \$\begingroup\$ @ThisSuitIsBlackNot Yes, file input is allowed. \$\endgroup\$ – Cows quack Oct 6 '15 at 16:47
  • \$\begingroup\$ Can you print "", an empty string? \$\endgroup\$ – OldBunny2800 Mar 7 '16 at 23:39

477 Answers 477

0
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MachineCode, 5 4 bytes

ebfe

This executes the machine code EB FE (JMP -2); -2 (0xFE) is the length of the instruction.

Try it online!

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0
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Tamsin, 10 bytes

main={''}.

Try it online!

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0
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Idris, 19 bytes

main:IO()
main=main

Haskell solution + type signature.

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0
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ink, 7 bytes

-(i)->i

Try it online!

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0
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Crystal, 6 bytes

loop{}

The loop keyword takes a block, which is here denoted by the curly brackets. I'm not sure I've seen any "real" (intended for use) Crystal code that uses loop instead of while, but I'd expect it to be used in the expanded form:

loop do
  # do something here
end
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0
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Aheui, 0 byte.


Since Aheui is befunge-like, this is infinite loop.

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0
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VTL-2, 7 bytes

2 #=1

# is the system variable in VTL-2 for line numbers, and it works to retrieve a line number or as a GOTO if given an assignment. So this is a trivial GOTO loop. The one interesting thing about it is that VTL-2 doesn't actually let you GOTO the current line number. It does GOTO the next largest line number when given a nonexistent line, however, so a one-line infinite loop will always work given that y is less than x for the program x #=y.

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0
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33, 4 bytes

Yes, this is a very simple answer:

1a[]

Nothing short of outright hardware failure will stop this from running. Or, y'know, stopping the program.

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0
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Forget, 37 bytes

const 0x0 1;cleanse 0x0;while 0x0;end

TIO

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  • \$\begingroup\$ What makes this non-competing? Languages created after the challenge are allowed. \$\endgroup\$ – TheOnlyMrCat Aug 7 at 8:26
  • \$\begingroup\$ @TheOnlyMrCat I guess things have changed \$\endgroup\$ – Benjamin Urquhart Aug 7 at 17:08
0
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Malbolge, 1787 bytes

This one doesn't rely on interpreter bug.

bP&A@?>=<;:9876543210/.-,+*)('&%$T"!~}|;]yxwvutslUSRQ.yx+i)J9edFb4`_^]\yxwRQ)(TSRQ]m!G0KJIyxFvDa%_@?"=<5:98765.-2+*/.-,+*)('&%$#"!~}|utyrqvutsrqjonmPkjihgfedc\DDYAA\>>Y;;V886L5322G//D,,G))>&&A##!7~5:{y7xvuu,10/.-,+*)('&%$#"yb}|{zyxwvutmVqSohmOOjihafeHcEa`YAA\[ZYRW:U7SLKP3NMLK-I,GFED&%%@?>=6;|9y70/4u210/o-n+k)"!gg$#"!x}`{zyxZvYtsrqSoRmlkjLhKfedcEaD_^]\>Z=XWVU7S6QPON0LKDI,GFEDCBA#?"=};438y6543s1r/o-&%*k('&%e#d!~}|^z]xwvuWsVqponPlOjihgIeHcba`B^A\[ZY;W:UTSR4PI2MLKJ,,AFE(&B;:?"~<}{zz165v3s+*/pn,mk)jh&ge#db~a_{^\xwvoXsrqpRnmfkjMKg`_GG\aDB^A?[><X;9U86R53ONM0KJC,+FEDC&A@?!!6||3876w4-tr*/.-&+*)('&%$e"!~}|utyxwvutWlkponmlOjchg`edGba`_XW\?ZYRQVOT7RQPINML/JIHAFEDC&A@?>!<;{98yw5.-ss*/pn,+lj(!~ff{"ca}`^z][wZXtWUqTRnQOkNLhgfIdcFaZ_^A\[Z<XW:U8SRQPOHML/JIHG*ED=%%:?>=~;:{876w43210/(-,+*)('h%$d"ca}|_z\rqYYnsVTpoRPledLLafIGcbE`BXW??TY<:V97S64P31M0.J-+G*(DCB%@?"=<;|98765.3210p.-n+$)i'h%${"!~}|{zyxwvuXVlkpSQmlOjLbafIGcbE`BXW??TY<:V97S64P31M0.J-+G*(D'%A@?"=<}:98y6543,1r/.o,+*)j'&%eez!~a|^tsx[YutWUqjinQOkjMhJ`_dGEaDB^A?[><X;9U86R53O20LKJ-HG*ED'BA@?>7~;:{y7x5.3210q.-n+*)jh&%$#"c~}`{z]rwvutWrkpohmPkjihafI^cba`_^A\[>YXW:UTS5QP3NM0KJ-HGF?D'BA:?>=~;:z8765v32s0/.-nl$#(ig%fd"ca}|_]yrqvYWsVTpSQmPNjMKgJHdGEa`_B]\?ZY<WVUTMR5PO20LK.IHA))>CB%#?87}}49zx6wu3tr0qo-nl*ki'hf$ec!~}`{^yxwvotsrUponQlkMihKIe^]EEZ_B@\?=Y<:V97S64P31M0.J-+GFE(C&A@?8=<;:{876w43s10qo-&%kk"'hf$ec!b`|_]y\ZvYWsVTpSQmlkNiLgf_dcba`C^]\?ZY;WV97SLK33HM0.J-+G*(D'%A$">!};|z8yw543t1r/(-,+*)(i&%fd"!~}|_t]xwvutslqTonmPkjLhKIeHFbEC_^A?[TSX;9UT7R4JIN1/K.,H+)E(&B%#?"~<}{987x/4ussr).o,+l)(h&ge#db~a_{^\x[YutWrTjinQOkNLhgJeG]\aDB^]@[=SRW:877LQP3N0FEJ-+**?DC&A#98=~|:98yx/4u21rp(',mk)(ig%|{"ca}`^z][wZXtWUqTRnQOkNLhKIedcFE`YB@@?ZYRW:UTS6QPO11F..CHGF)(CB;@#>!~;XzV7gwu-QrrqMoJIkZF'WC$#AbQ`_{^L9wI64"VDConzl+j);JJ%qGFEZ~}]{ygwRuc8aSq44"H1Y.iV,e*RQ

Try it online!

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0
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GOLANG : 32 Bytes

package main;func main(){main()}

One more solution :

package main;func main(){for{}}
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  • 1
    \$\begingroup\$ Welcome to Code Golf! You can eliminate two of the spaces. Try it online! \$\endgroup\$ – Dennis Aug 7 at 13:18
0
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Oasis, 2 bytes

1b

TIO

Explanation

1  Starting from a(1)
 b Recurse all the way down (i.e. do a(n-1))
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0
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Stax, 1 bytes

G

Run and debug it

G goes to the beginning of the program...

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0
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ABC (Esoteric), 1 byte

l

Loops back to the beginning.

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0
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And, 0 bytes


No && exit, therefore loops forever.

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0
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A0A0, 2 bytes

G0

Goes 0 lines below the current line.

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0
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Fastlane, 0 bytes


The pointer speed defaults to 1 and wraps around; there isn't a $ instruction to halt the pointer in this program.

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0
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@, 2 bytes

¤

Loops forever, takes arbitary input and has no output.

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0
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><>, 0 bytes


There's no ; instruction to halt the program, so it runs forever.

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  • \$\begingroup\$ It may not work on every interpreter (it doesn't work on tio.run), but it seems to work on fishlanguage.com \$\endgroup\$ – mbomb007 Sep 7 at 17:15
0
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///, 3 bytes

///

Try it online!

This replaces nothing with nothing. It runs forever because when it replaces nothing with nothing, it has to replace that nothing with another nothing, and it does this indefinitely.

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0
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QWOP, 2 bytes

OO

Explanation

The command O return[s] the pointer to the last O, if one exists. So this will run indefinitely without producing output.

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0
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Kipple (cipple), 6 5 bytes

1>a(a

Pretty simple, just pushes 1 to stack A, and then begins a loop that only ends if stack A is empty

-1 byte, since the ending bracket isn't necessary in cipple for some reason

Try it online!

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0
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Element, 3 bytes

!{]

Negates top of stack & executes while.

TIO

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0
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Rust, 17 bytes

fn main(){loop{}}

Just for fun :P

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0
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International Phonetic Esoteric Language, 3 bytes (WIP language)

ɘ0e

What the code does is push 0, then check if the stack is falsy, which 0 is. Then it jumps, without any output.

No TIO interpreter yet, but is runnable by cloning the repository above, and calling python3 main.py "code here".

ɘ0e
ɘ   ; begin falsy jump
 0  ; push 0
  e ; pop, if falsy jump; else end falsy jump
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0
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Whenever: 4 bytes

1 1;

Is actually an example from the specification. The instruction causes line 1 to put itself back on the to-do list.

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-2
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Python: 15 bytes

while 3>1:
    x=1
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  • 5
    \$\begingroup\$ Just as a note, there is a leaderboard on this post. You can see the current best scoring python answer here. \$\endgroup\$ – FryAmTheEggman May 17 '16 at 14:37

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