29th International Obfuscated C Code Contest Official Guidelines
All Rights Reserved. Permission for personal, education or non-profit use is granted provided this copyright and notice are included in its entirety and remains unaltered. All other uses must receive prior permission in writing by contacting the Judges.
Guidelines Version
Guidelines
These Guidelines are hints and suggestions, NOT Rules.
While submissions that violate the Guidelines are allowed, submissions that remain within the Guidelines are preferred.
You are encouraged to review the following FAQs:
While the contest is open, you may modify your previously uploaded submission by rebuilding your submission with the mkiocccentry toolkit, and then re-uploading it to the same slot number on the submit server.
Be sure to read the Rules.
Guidelines for Rule 1 - C program
Jump to: top
Guidelines for Rule 2 - Size restrictions
Your submission must satisfy BOTH the Rule 2a - Gross Size AND Rule 2b - Net Size rules.
To check your code against
Rule 2 - Size restrictions, use the
iocccentry(1) tool. For example:
iocccsize prog.cThe iocccsize(1) algorithm can be summarized as follows:
The size tool counts most C reserved words (keyword, secondary, and selected preprocessor keywords) as 1. The size tool counts all other bytes as 1 excluding ASCII whitespace, and excluding any ‘
;’, ‘{’ or ‘}’ followed by ASCII whitespace, and excluding any ‘;’, ‘{’ or ‘}’ byte immediately before the end of file.ASCII whitespace includes ASCII tab, ASCII space, ASCII newline, ASCII formfeed, and ASCII carriage return.
When ‘
;’, ‘{’ or ‘}’ are within a C string, they may still not be counted by the IOCCC size tool.
In cases where the above summary and the algorithm implemented by
iocccsize(1) conflict, the algorithm implemented by the minimum
required version of iocccsize(1) is preferred by the
Judges.
Make sure iocccsize does not flag any issues with your prog.c.
NOTE: by default iocccsize will only report the size, unless the
code surpasses the limit.
There a much less need to #define C reserved words in an effort to
get around the size limits of Rule 2 - Size
restrictions because of the iocccsize(1)
algorithm.
Yes Virginia, the previous guideline sentence is an important hint!
Don’t expect the Rule 2 - Size restrictions to change any time soon.
See the FAQ on “How has the Rule 2 size restrictions rule changed over the years?”.
Jump to: top
Guidelines for Rule 3 - Register for the IOCCC
It can take a few days to process your registration and for the server to email your details, therefore make sure to allow yourself ample time to register and submit your entries; DO NOT WAIT UNTIL THE FINAL DAYS to register! The Judges are NOT responsible for delayed or lost email or for those who wait until the last minute to try to register!
See the FAQ on “How to register for the IOCCC”.
See the FAQ on “Entering the IOCCC: the bare minimum you need to know”.
Jump to: top
Guidelines for Rule 7 - Original Work
While it is NOT required, you are allowed to use tools or services such as:
- Code generators
- Static and runtime code analysis tools
- Machine learning tools
- Natural language models
- Large language models (LLMs)
- Code copilot tools
- So called “AI services”
- Etc.
The IOCCC has a rich history of remarkable winning entries created by
authors who skillfully employed various techniques (often their own
tools) to develop their code. If you do make use of such tools or
services, then we ENCOURAGE you to describe how you used such tools
in your remarks.md file.
See the FAQ on “May I use AI, LLM, Virtual coding assistants, or similar tools to write my submission?”.
Jump to: top
Guidelines for Rule 8 - Submitting requirements
Do NOT register more than one account just to try and get around the limit on the number of submission slots, because if you do and we discover that you did so your submissions will be rejected for violating the rules.
Jump to: top
Guidelines for Rule 9 - No interactive compiling allowed
Don’t forget that the building of your program should be done WITHOUT human intervention. So don’t do things such as:
prog: prog.c
#echo this next line requires data from standard input
cat > prog.c
${CC} prog.c -o progHowever, you can do something cute such as making your program do
something dumb (or cute) when it is built ‘automatically’, and when it
is run with a human involved, do something more clever. For example,
one could put in their Makefile:
prog: prog.c
${CC} prog.c -DNON_HUMAN_COMPILE -o prog
@echo "See remarks section about alternate ways to compile"and then include special notes in your remarks.md file for alternate
/ human intervention based building.
Jump to: top
Guidelines for Rule 11 - Legal rule abuse
We do realize that there are holes in the Rules, and invite submitters to attempt to apply creative rule interpretation. A rule abuse though, even if not rewarded, may result in a subsequent rule change for future contests.
We sometime award ‘Best abuse of the rules’ or ‘Worst abuse of the rules’, or some variation, to a submission that creatively attempts to exploit a holes in the Rules.
When we do need to plug a hole in the Rules or Guidelines, we will attempt to use a very small plug, if not smaller.
Or, maybe not. :-)
Legal rule abuse may involve, but is not limited to, doing things that are technically allowed by the Rules and yet do not fit the spirit of what we intended to be submitted.
Legal abuse of the Rules is NOT an invitation to violate the Rules (especially Rule 17 - Use mkiocccentry). A submission that violates the rules in the opinion of the Judges, WILL be disqualified. RULE ABUSE CARRIES A CERTAIN LEVEL OF RISK!
If you intend to abuse the Rules, indicate so in your
remarks.md file. You MUST try to justify, plead, beg, why you
consider your rule abuse to be allowed under the Rules.
Humor or creativity help plead a case.
As there is no guarantee that you will succeed, you might consider submitting an alternate version that conforms to the Rules, if it might otherwise be interesting; one that does not abuse the Rules and one that does, making sure to note in the one that does not abuse the rules that this is another version, so that the Judges do not assume you uploaded it by mistake.
If you do bypass the mkiocccentry(1) warnings about
Rule 2a - Gross Size
and/or about
Rule 2b - Net Size
or any other
rule and submit it anyway, you MUST try to justify why the
Judges should not reject your submission due to a rule
violation, and you would be wise to do this towards the top of your
remarks.md file so as not to be overlooked.
We are often asked why the contest Rules and Guidelines seem strange or contain mistakes, flaws, or grammatical errors. One reason is that we sometimes make genuine mistakes, but in many cases such problems, flaws or areas of confusion are deliberate.
Changes to Rules and Guidelines in response to rule abuses, are done in a minimal fashion. Often we will deliberately leave behind holes (or introduce new ones) so that future rule abuse can continue. A clever author should be able to read and “drive a truck through the holes” in the Rules and Guidelines.
At the risk of stating the obvious, this contest is a parody of the software development process. The Rules and Guidelines are only part of the overall contest. Even so, one might think the contest Rules and Guidelines process as a parody of the sometimes tragic mismatch between what a customer (or marketing) wants and what engineering delivers. Real programmers must face obfuscated and sometimes conflicting, ballooning specifications, and requirements from marketing, sales, product management and even from customers themselves on an all too regular basis. This is one of the reasons why the Rules and Guidelines are written in obfuscated form.
Jump to: top
Guidelines for Rule 12 - UTF-8
The IOCCC no longer discourages the use of multibyte UTF-8 characters
in C code.
Guidelines for Rule 13 - No carriage returns in prog.c
We DISLIKE C code with trailing control-M’s (\r or \015) that
results in compilation failures.
Some non-UNIX/non-Linux tools such as MS Visual C and MS Visual C++ leave trailing control-M’s on lines. Users of such tools should strip off such control-M’s before submitting their submissions. In some cases tools have a “Save As” option that will prevent such trailing control-M’s being added.
Jump to: top
Guidelines for Rule 15 - GNU Makefile
Submissions will be judged in an environment that has no IDE. Any submission that fails to compile/build because it requires an IDE will be rejected.
See the FAQ on “What are the detailed recommendations for a submission Makefile?”.
Jump to: top
Guidelines for Rule 17 - Use mkiocccentry
See the
FAQ on “What should I do with the try.sh and try.alt.sh
scripts?”.
See the
FAQ on “What is a .auth.json file?”.
See the
FAQ on “What is a .info.json file?”.
See the FAQ on “How can I validate my submission directory?”.
See the FAQ on “What permissions may my files be and what if I need different permissions?”.
See the FAQ on “What are the detailed recommendations for a submission Makefile?”.
See the FAQ on “What are the details behind Rule 17 - Use mkiocccentry?”.
Jump to: top
General Guidelines
Overall Guidelines
You are encouraged to examine the winners of previous contests.
Because the Rules change from year to year, some past winning entries may be rejected this year. What was was unique and novel one year might be ‘old’ the next year.
A submission is usually examined in a number of ways. We typically apply a number of tests to a submission:
- look at the original source
- C pre-process the source ignoring
#includelines - C pre-process the source ignoring
#defineand#includelines - run it through a C beautifier (such as
clang-format(1)) - examine the algorithm
- compile it (with flags to enable all warnings)
- execute it
- …and various other things only we know about :-)
You should consider how your submission looks in each of the above tests. You should ask yourself if your submission remains obscure after it has been ‘cleaned up’ by the C pre-processor and a C beautifier.
Your submission need not pass all of the above tests as in certain cases, a test is not important.
Submissions that compete for the ‘strangest/most creative source layout’ need not do as well as others in terms of their algorithm.
Given two submissions, we are more inclined to pick the submission that does something interesting when it’s executed.
IMPORTANT: Be sure that your submission works as documented in
your remarks.md file.
We sometimes make an effort to debug a submission that has a slight problem, particularly in or near the final round. On the other hand, we have seen some otherwise excellent submissions fall down because they didn’t work as documented.
If you submission has bugs and/or mis-features, you are MUCH BETTER
off documenting such bugs and/or mis-features in your remarks.md
file.
Consider an example of a prime
number printing program
that claims that 16 is a prime number. Noting such a bug in your
remarks.md file could save your submission:
“this submission sometimes prints the 4th power of a prime by mistake”
Sometimes a strange bug or (mis-)feature can even help the submission! Of course, a correctly working submission might be better.
We tend to look down on a prime
number printer that claims
that 16 is a prime number. Clever people will note that 16 might be
prime under certain conditions. :-) Wise people, when submitting
something clever will fully explain such cleverness in their
submission’s remarks.md file.
People who are considering to just use some complex mathematical function or state machine to spell out something such as “hello, world!” really really, and we do mean REALLY, do need to be more creative.
Consider using misleading or subtle tricks layered on top of or under an appropriate level of obfuscation.
A clean looking program with misleading comments and variable names might be a VERY GOOD START to a great submission!
Try to avoid submissions that play music that some people believe is copyrighted music.
Did we remember to indicate that programs that blatantly use some complex state machine to do something simple, are boring? We think we did. :-)
Given two versions of the same program, one that is a compact blob of code, and the other that is formatted more like a typical C program, we tend to favor the second version. Of course, a third version of the same program that is formatted in an interesting and/or obfuscated way, would definitely win over the first two!
Remember, you can submit more than one submission. See the Rules for details (in particular, Rule 8 - Submitting requirements).
Please note that the C source below, besides lacking in obfuscation, is NOT the smallest C source file that when compiled and run, dumps core:
main;Unless you specify -fwritable-strings (see COTHER in the example
Makefile, described in the
FAQ on “What are the detailed recommendations for a submission
Makefile”), do not
assume this sort of code will work:
char *T = "So many primes, so little time!";
...
T[14] = ';'; /* modifying a string requires: -fwritable-strings */Even so, one should probably not assume that this is universally accepted.
Initialized char arrays are OK to write over. For instance, this is OK:
char b[] = "Is this OK";
b[9] = 'k'; /* modifying an initialized char array is OK */Jump to: top
Our Likes and Dislikes
We VERY MUCH LIKE submissions that use an edited variant of the
example Makefile, as described and linked to in the
FAQ on “What are the detailed recommendations for a submission
Makefile?,
renamed as Makefile of course.
This makes it easier for the Judges to test your submission. And if your submissions wins, it makes it easier to integrate it into the Official IOCCC winner website.
We VERY MUCH LIKE submissions that have some educational value.
This does NOT mean that your submission should not be obfuscated
but rather that the IOCCC has moved away from the idea of “spoilers”.
You should not encrypt or rot13 content in your remarks.md file.
The above statement does not mean encryption/decryption tools will not
win, nor does it mean that if you have such a submission that you could
not encrypt some remarks (such as obfuscation details), but if you do
so please put them in a separate file and indicate how to decipher it.
Please do NOT use any cipher to encrypt your remarks.md.
It is VERY MUCH appreciated if your remarks or prog.c have some
educational value. And although educational value is not required, it
is an EXCELLENT bonus.
We LIKE submissions that use an edited version of the try.sh
example script (and if you have alternate code, the same applies with
the try.alt.sh script):
Of course, it is quite possible that only one invocation is possible, so it is not necessarily detrimental to your submission if you do not include one, though we do like interesting and creative uses of submissions. See also the FAQ on “submitting try.sh and try.alt.sh scripts”.
We tend to DISLIKE programs that:
- are very hardware specific
- are very OS version specific (
index(3)/strchr(3)differences are OK, but sockets/streams specific code is likely not to be) - dump core or have compiler warnings (it is OK only if
you warn us in your
remarks.mdfile) - won’t compile or run in a Single UNIX Specification (UNIX-like) environment
- depend on a utility or application not normally found in systems that conform to the Single UNIX Specification
- abuse the build file to get around the size limit
- obfuscate by use of ANSI trigraphs
- obfuscate by use of digraphs
- are larger than they need to be
- have more lines than they need to have
- are “blob-ier” (just a pile of unformatted C code) than they need to be
- are rather similar to previous winners :-(
- are identical to previous losers :-)
- that mandate the exclusive use of a specific Integrated Development Environment (IDE)
In order to encourage submission portability, we DISLIKE submissions that fail to build unless one is using an IDE. For example, do not mandate that one must use Microsoft Visual Studio to compile your submission.
Jump to: top
About C preprocessor
Doing masses of #defines to obscure the source has become ‘old’. We
tend to ‘see thru’ masses of #defines due to our pre-processor tests
that we apply. Simply abusing #defines or -Dfoo=bar won’t go as
far as a program that is more well rounded in confusion.
Many C compilers DISLIKE the following code, and so do we:
#define d define
#d foo /* <-- don't expect this to turn into #define foo */In other words, it is a compilation error, and in order to get older IOCCC winning entries that did this to compile, we had to update them to not do this.
When declaring local or global variables, you should declare the type:
int this_is_fine;and NOT like this:
this_is_not; /* <-- Try to avoid implicit type declarations */We really DISLIKE submissions that make blatant use of #include
of large data files to get around the source code size limit. This does
not mean #include of standard header files, just files you provide,
or system files such as /usr/share/dict/words.
On 28 January 2007, the Judges rescinded the requirement that the #
in a C preprocessor directive must be the 1st non-whitespace byte.
About compilers
We tend to like less a submission that requires either gcc
OR clang. We prefer submissions that can compile under
BOTH gcc AND clang. Hint!
We RECOMMEND that the compiler flags you use in your submission’s
Makefile are supported by BOTH gcc AND clang.
We DISLIKE the use of obscure compiler flags, especially if gcc
and/or clang do not support it. We suggest that you not use any
really obscure compiler flags if you can help it.
About nested functions
One side effect of the above is that you cannot assume the use of nested functions such as:
int main() {
| void please_dont_submit_this() {
| printf("The machine that goes BING!!\n");
}
| please_dont_submit_this();
}On 2012 July 20, the Judges rescinded the
encouragement of nested functions. Such constructions, while
interesting and sometimes amusing, will have to wait until they are
required by a C standard that are actually implemented in BOTH
gcc AND clang.
We DISLIKE submissions that require the use of
-fnested-functions.
About variadic functions
If your submission uses functions that have a variable number of
arguments, be careful. Systems implement va_list in a wide
variety of ways. Because of this, a number of operations using
va_list are not portable and must not be used:
- assigning a non-
va_listvariable to/from ava_listvariable - casting a non-
va_listvariable into/from ava_listvariable - passing a
va_listvariable to a function expecting a non-va_listarg - passing a non-
va_listvariable to a function expecting ava_listarg - performing arithmetic on
va_listvariables - using
va_listas a structure or union
In particular, do not treat va_list variables as if they were a char **.
We DISLIKE the use of varargs.h. Use stdarg.h instead.
About I/O functions
We DISLIKE the use of gets(3). Use fgets(3) instead.
About tarballs
We tend to DISLIKE the blatant use of tarballs in an attempt to
simply get around the extra file number limit. We realize there may be
cases where a tarball containing a number of extra files may be needed.
Such a need for a tarball MUST be explained in the remarks.md
file.
On gotos
About exit(3)
The exit(3) function returns void. Some broken systems have
exit(3) return int; your submission should assume that exit(3)
returns a void.
What it means to be small
Small programs are best when they are short, obscure and concise. While such programs are not as complex as other winners, they do serve a useful purpose: they are often the only program that people attempt to completely understand. For this reason, we look for programs that are compact, and are instructional.
Programs that claim to be the smallest C source that does something, really better be the smallest such program or they risk being rejected because they do not work as documented.
We suggest that you avoid trying for the ‘smallest self-replicating’ source. The smallest, a zero byte entry, won in 1994.
What a one-liner means
About blobs of code
We want to get away from source that is simply a compact blob of bytes. REALLY TRY to be more creative than blob coding. HINT!
Unless you are cramped for space, or unless you are entering the ‘Best one liner’ category, we suggest that you format your program in a more creative way than simply forming excessively long lines.
About size restrictions
The Makefile should not be used to try and get around the size limit.
It is one thing to make use of a several -Ds on the compile line to
help out, but it is quite another to use many bytes of -Ds in order
to try and squeeze the source under the size limit.
Please do not use things like gzip(1) to get around the size limit.
This was done years ago; please try to be much more creative.
Your source code, post-pre-processing, should not exceed the size of Microsoft Windows. :-)
About environment
The program must compile and link cleanly in a Single UNIX Specification (UNIX-like) environment. Therefore do not assume the system has a windows.h include file:
#include <windows.h> /* we DISLIKE this */Other windows, on the other hand, might be OK: especially where “X marks the spot”. Yet on the third hand, windows are best when they are “unseen” (i.e., not dirty). :-)
You may compile and use your own programs. If you do, try to build and execute from the current directory. This restriction is not a hard and absolute one. The intent is to ensure that the building of your program is reasonably portable.
We prefer programs that are portable across a wide variety of UNIX-like operating systems (e.g., Linux, GNU Hurd, BSD, UNIX, macOS, etc.).
We prefer code that can run on either a 64-bit or 32-bit processor. However, it is UNWISE to assume it will run on an some Intel-like x86 architecture**.
While programs that only run in a specific word size are OK, if you have to pick, choose a 64-bit word size.
If your submission MUST run only on a 64-bit or 32-bit
architecture, then you MUST specify the -arch on your command
line (see ARCH in the example Makefile, described in the FAQ on
“What are the detailed recommendations for a submission
Makefile?.
Do not assume a processor word size without specifying -arch. For
example:
ARCH= -m64Note, however, that some platforms will not necessarily support some
architectures. For instance, more recent versions of macOS do NOT
support 32-bit, and more than zero Judges use it!
About X
X client submissions should be as portable as possible. Submissions that adapt to a wide collection of environments will be favored.
For example, don’t depend on a particular type or size of display.
Don’t assume the use of a particular browser. Instead assume a generic browser that forms to a widely used W3C standard.
Don’t assume a particular sound sub-system or video driver is installed in the OS. Instead, make use of a well known and widely available open source program (one that actually works) to display audio/visual data.
X client submissions should avoid using X related libraries and software that are not in wide spread use.
As of Red Hat RHEL9.0, the X.org server is deprecated. See the FAQ on “Xorg deprecation” for more details. This does not mean that a submission using this will necessarily be rejected, but it would be better if it can support Wayland in some way or another.
We DISLIKE submissions that use proprietary toolkits such as the
M*tif, Xv*ew, or OpenL*ok toolkits, since not everyone has them.
Use an open source toolkit that is widely and freely available instead.
X client submissions should try to not to depend on particular items in
.Xdefaults. If you must do so, be sure to note the required lines in
the your remarks.md file.
X client submissions should also not depend on any particular window manager.
About libcurses
One should restrict libcurses to portable features found on both BSD and Linux curses.
Jump to: top
About ASCII TAB
We DISLIKE the use of ASCII tab characters in markdown files, such
as in the required remarks.md file.
We don’t mind the use of ASCII tab characters in your C code. Feel free to use ASCII tab characters if that suits your obfuscation needs. If is perfectly OK to use tab characters elsewhere in your submission, just not in markdown files as this tends annoy us when it comes time to rendering your markdown content as it complicates the process.
If you do use ASCII tab characters in your non-markdown files, be aware that some people may use a tab stop that is different than the common 8 character tab stop.
PLEASE observe our markdown guidelines when
forming your submission’s remarks.md file. And if your submission
contains additional markdown files, please follow those same Guidelines
for those files.
See also Rule 4 - Required files, and the FAQ on “markdown”.
Jump to: top
About remarks.md
You are better off explaining what your submission does in your
remarks.md file section rather than leaving it obscure for the
Judges as we might miss something and/or be too tired
to notice.
We freely admit that interesting, creative or humorous comments in your
remarks.md file help your chances of winning. If you had to read so
many twisted submissions, you too would enjoy a good laugh or two. We
think the readers of the contest winners do as well. We do read your
remarks.md content during the judging process, so it is worth your
while to write a remarkable remarks.md file.
It is a very good idea to, in your remarks.md file, tell us why you
think your submission is obfuscated. This is particularly true if your
submission has some very subtle obfuscations that we might otherwise
overlook. <<– Hint!
Anyone can format their code into a dense blob. A really clever author will try formatting their submission using a “normal” formatting style such that at first glance (if you squint and don’t look at the details) the code might pass for non-obfuscated C. Deceptive comments, and misleading formatting, in some cases, may be a plus. On the other hand, a misleading code style requires more source bytes.
If you do elect to use misleading formatting and comments, we suggest
you remark on this point in your remarks.md where you talk about why
you think your submission is obfuscated.
If you are pushing up against the size limits, you may be forced into creating a dense blob. Such are the trade-offs that obfuscators face!
We LIKE reading remarks.md files, especially if they contain
useful, informative, and even humorous content about your submission.
Yes, this is a hint. :-)
We RECOMMEND you put a reasonable amount effort into the content of
the remarks.md file: it is a required file for a reason. :-)
Jump to: top
Miscellaneous
While we recognize that UNIX is not a universal operating system, the contest does have a bias towards such systems. In an effort to expand the scope of the contest, we phrase our bias to favor the Single UNIX Specification (UNIX-like).
You are well advised to submit code that conforms to the Single UNIX Specification Version 4.
To quote the Judges:
We LIKE programs that:
- are as concise and small as they need to be
- do something at least quasi-interesting
- are portable
- are unique or novel in their obfuscation style
- make use of a NUMBER OF DIFFERENT TYPES OF OBFUSCATIONS! <== HINT!!
- make us laugh and/or throw up :-) (humor really helps!)
- make us want to eat good chocolate
Some types of programs can’t excel (anti-tm) in some areas. Your program doesn’t have to excel in all areas, but doing well in several areas really does help.
Try to be even more creative!
If there are limitations in your submission, you are highly encouraged
to note such limitations in your remarks.md file. For example if
your submission factors values up to a certain size, you might want to
state:
This submission factors values up
2305567963945518424753102147331756070. Attempting to factor larger values will produce unpredictable results.
The Judges might try to factor the value -5, so you want to might state:
This submission factors positive values up
2305567963945518424753102147331756070. Attempting to factor large values will produce unpredictable results.
However the Judges might try to also factor 0, so you might want to state:
This submission factors values between 1 and
2305567963945518424753102147331756070. Attempting to factor values outside that range will produce unpredictable results.
Moreover they might try to also factor 3.5 or 0x7, or Fred, so you want to might state:
This submission factors integers between 1 and
2305567963945518424753102147331756070. Attempting to factor anything else will produce unpredictable results.
You submission might be better off catching the attempt to factor bogus values and doing something interesting. So you might want to code accordingly and state:
This submission factors integers between 1 and
2305567963945518424753102147331756070. Attempting to factor anything else will cause the program to insult your pet fish Eric.
The Judges might not have a pet fish named Eric, so you might want to state:
This submission factors integers between 1 and
2305567963945518424753102147331756070. Attempting to factor anything else will cause the program to insult your pet fish Eric, or in the case that you lack such a pet, will insult the pet that you do not have.
When all other things are equal, a submission with fewer limitations will be judged better than a submission with lots of limitations. So you might want to code accordingly and state:
This submission attempts to a factor value of any size provided that the program is given enough time and memory. If the value is not a proper integer, the program might insult a fish named Eric.
Do not fear if you’re not 100% sure of the significance of
2305567963945518424753102147331756070 as it is not of prime
importance: or is it? :-)
Jump to: top
Guidelines for the mkiocccentry toolkit
The IOCCC submit server, and related services use the most recent version of the mkiocccentry toolkit: submissions that package using older versions of the mkiocccentry toolkit are LIKELY to be REJECTED!
You REALLY SHOULD use the latest mkiocccentry toolkit to package your submission as submissions that use an older version are WILL be REJECTED!
The mkiocccentry(1) tool runs a number of checks by way of these
mkiocccentry toolkit
tools:
iocccsize(1)txzchk(1)fnamchk(1)chksubmit(1)chkentry(1)
Do NOT use txzchk(1) or fnamchk(1) command line options that
are labelled “for TESTING purposes” in their respective man pages.
Do NOT use fnamchk(1) command line options that are labelled
“for TESTING purposes” in the fnamchk(1) man page.
Do NOT use chksubmit(1) command line options that are labelled
“for the use by the Judges only” in the chksubmit(1) man page.
Similarly do NOT use chkentry(1) command line options marked
“for the use by the Judges only” in the chkentry(1) man page.
To view mkiocccentry toolkit man pages, while your current directory is the top of the source tree:
man soup/man/man1/mkiocccentry.1
man soup/man/man1/iocccsize.1
man soup/man/man1/txzchk.1
man test_ioccc/man/man1/fnamchk.1
man soup/man/man1/chksubmit.1
man soup/man/man1/chkentry.1The above man(1) commands will show the toolkit man pages without
having to install them first.
So that you do not have to repeatedly answer all the mkiocccentry(1)
questions, use mkiocccentry -a answers ... to create a file
containing the answers you first give, and later enter mkiocccentry -i answers ... to reuse those same answers.
The mkiocccentry -A answers ... does the same thing except that the
answers file will be overwritten.
The mkiocccentry -i answers ... will still be required to confirm
“Yes/No” questions.
Use mkiocccentry -Y -i answers ... to force a yes answers with great
caution because it might force a yes answer to something you do
NOT want, such as a change in your code that violates a detected
rule.
The mkiocccentry -i answers ... will still be required to confirm
“Yes/No” questions. While mkiocccentry -Y -i answers ... will force
yes answers, use with great caution, because it might force a yes
answer to something you do NOT want.
To help with not having to repeatedly enter a UUID, put your UUID into
a file and use mkiocccentry -u uuidfile ..., or use mkiocccentry -U UUID ... to give the UUID on the command line. If you also use -a answers or -A answers the UUID will be recorded, assuming it is a
valid UUID.
If you wish to test that your submission passes the
mkiocccentry(1) tests without having to type in answers each time,
you can use the -d or -s seed option to mkiocccentry for the tool
to pseudo-randomly create answers for you. For example:
mkiocccentry -d workdir topdir cd workdir/UUID-slot_num && tar --format=v7 -cJf submit.UUID-slot_num.timestamp.txz UUID-slot_numIn many places the mkiocccentry(1) tool will prompt you to verify
what you input, allowing you to correct details as you go along.
The mkiocccentry(1) tool will use code from iocccsize(1) which
detects a number of issues (such as Rule 2 - Size
restrictions) that you may ignore, however
ignoring such issues comes with a SIGNIFICANT level of risk!
Once the submission directory has been constructed the
mkiocccentry(1) tool will run chksubmit(1) to verify everything is
well, before forming the tarball.
Once the tarball is formed mkiocccentry(1) will run txzchk(1),
which will also run fnamchk(1), as part of its algorithm.
If mkiocccentry encounters an error, the program will exit and
the xz compressed tarball will NOT be generated: this is a
feature, not a bug!
If you encounter a bug with the mkiocccentry
toolkit PLEASE run the
bug_report.sh script to help us out here!
README.mdindex.htmlprogprog.altprog.alt.oprog.orig.c- filenames matching the
[0-9][0-9][0-9][0-9]_*.tar.bz2file glob
See the
FAQ on “How do I report bugs in an mkiocccentry
tool?”.
See Rule 11 - Legal rule abuse
for warnings about ignoring mkiocccentry(1) tool warnings.
See the
FAQ on “What is the fnamchk tool?”.
See the FAQ on “What is mkiocccentry in simple terms?”.
See the FAQ on “What is the mkiocccentry tool, how do I obtain it and how do I use it”.
Jump to: top
Fun😄damental Guidelines
The reason for the times of day are so that key IOCCC events are calculated to be a functional UTC time. :-)
At least 2 of several reasons for selecting the prime, 2503, for Rule 2b - Net Size may be found on the “Curios!” about 2503.
The 2503 value for Rule 2b - Net Size is a decimal anagram of the number of the kernel disk pack of one of the judge’s BESM-6.
Some people might question what actually constitutes a valid JSON file, given the state of the “so-called” JSON spec. :-)
We prefer programs that do not require a fish license: crayons and cat detector vans not withstanding.
While those who are used to temperatures found on dwarf planets (yes Virginia, dwarf planets ARE planets!), such as Pluto, might be able to explain to the Walrus why our seas are boiling hot, the question of whether pigs have wings is likely to remain a debatable point to most.
At least one judge prefers to maintain the use of the leap-second as part of the world’s time standard. If your code prints time with seconds, we prefer that your code be capable of printing the time of day during a leap-second where the value in seconds after the minute mark is 60.
The Judges, as a group, have a history giving wide degree of latitude to reasonable submissions. And recently they have had as much longitudinal variation as it is possible to have on Earth. :-)
You are in a maze of twisty guidelines, all different.
There are at least zero Judges who think that Fideism has little or nothing to do with the Judging process.
All generalizations are false, including this one. – Mark Twain
This could be the only guideline that contains the word fizzbin.
However, do you know how to play fizzbin? You do?!? (Except on Tuesday?)
OK, there are actually 2 guidelines that contain the word fizzbin, unless you count this one, in which case there are 3. :-)
NOTE: The previous guideline in this spot has been replaced by this guideline:
Any complaints about the above guideline could be addressed to the Speaker of the House of Commons, or to the speaker of your national parliament should you have one.
We believe that Mark Twain’s quote:
Get your facts first, then you can distort them as you please.
… is a good motto for those writing code for the IOCCC.
Jump to: top
Further Reading
See the Official IOCCC website news for additional information.
For questions or comments about the contest, see Contacting the IOCCC.
Be SURE to review the current IOCCC Rules and Guidelines as they often change year to year. Especially prior to submitting to the contest.
For the latest IOCCC news, follow the IOCCC on Mastodon. See our FAQ on “Mastodon” for more information.
Also consider joining the IOCCC Discord
Server for the latest news,
discussions about The Rules, questions for the Judges, and C in
general.
Jump to: top
