The International Obfuscated C Code Contest

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Q: How many entries do you receive each year?
A: By tradition, we do not say.

Q: How many judging rounds do you have?
A: Are you trying to trick us? We will not say that either.

Q: I cannot get entry xyzzy from year 19xx to compile!
A: Some winners, particularly winners from long ago, no longer compile on more modern systems because the C language has evolved (i.e. the modern C compilers are much more strict in what they accept as a valid program), or the entry depended on operation system and library features that where common back then but are different/missing today.
E.g. it is highly unlikely that you'll be able to execute 1984/mullender on a computer you're using to read this FAQ.

Q: I found a bug in a previous winner, what should I do?
A: We do not ``maintain'' the contest winners. The code is made available on an ``AS IS'' basis. If you have a FIX for a entry, we suggest that you try and EMail it to the authors and to CC: us using the instructions on the contacting the IOCCC Judges page.
IF you have a FIX, and IF the author does not object, and IF your fix looks reasonable, we will add a web link to a copy of your EMail message for others to see.

Q: Are there types of entries that are submitted so frequently that the judges get tired of them?
A: Yes, there are types of entries that show up over and over again.
The guidelines say:

We tend to dislike programs that:
  • are similar to previous winners
  • We like variety. However too often we see (please look at the winning examples given to be aware of the level of the competition):

    HINT: It is not fatal to send in those types of entries, it is just MUCH HARDER to win. Such an entry would have to do something really unique and interesting to even make it into the final judging rounds. Entries that re-use these 'worn out' themes frequently lose to other entries that do something different.

    HINT: If you really MUST send in an entry based on an 'over-used theme', be sure that it is obfuscated in several new and novel ways. Be sure to clearly explain near the beginning of your remarks why you are submitting a entry based on an 'over-used theme' and why the judges should not simply toss it out as being boring.

    Q: What should I write in the 'remark' section of my entry, if anything at all?
    A: As much or as little as you wish.

    What helps:

    What does not help:

    Q: I am confused: what should I put to the 'build' section?
    A: The 'build' section must contain UNIX shell-style commands to compile your C language entry in a file named prog.c and produce an executable file. More than one command is allowed, as far as the size rule is followed. Usually one (or more) of these commands will be an invocation of a C compiler (use cc or gcc), but there may be exceptions (or not anymore, see 2000/tomx).
    If your entry depends on a particular source file name during compilation or execution, you will have to put a line

    cp prog.c desired_name.c
    before the compiler invocation line.
    If in doubt, put
    cc -o prog prog.c
    in the 'build' section.

    Q: What happened to the winners for 1997, 1999 and 2002?
    A: There are none. There was no IOCCC in those years.

    Q: Why don't you publish non-winners?
    A: Because the publication on the IOCCC site IS the award! Anyone is free to put their IOCCC hopefuls, lookalikes and/or non-winners on their web page for everyone to see.

    Q: How much time does it take to judge the contest?
    A: It takes a fair amount of time to setup, run, answer EMail, process (note that we do not contact the author if an entry does not compile or does not work as advertised, we might attempt to fix obvious compilation problems or incompatibilities, but no more than that - so be sure that your entry does work on at least a couple different platforms, at least one of them being UNIX or POSIX-conforming) entries, review entries, trim down the set entries to a set of winners, doing the write-up of the winners, announcing the winners, reviewing final edits of the winning entry set, posting the winners, being flamed :-), tell folks who send in late entries to wait until the next contest, etc... It takes a few weekends and a number nights of study and work ... which is hard given that we are busy with many other activities as well.

    Q: What platform should I assume for my entry?
    A: Your entry must compile with GCC and run under at least one flavor of UNIX (e.g. Linux or Solaris). To improve chances to win, it should work under both BSD and SysV style UNIX (think stty cbreak), and should not depend on endianness. If it can compile and run on Windows and/or Mac (see 2000/thadgavin), even better.

    Q: I would like to mirror the IOCCC web site. May I do so?
    A: Please see: for more information.

    Q: I want to publish some parts of the IOCCC in an article, or book, or newsletter, or use then in class/instructional notes, or quote from the IOCCC. May I do so?
    A: Please ask the IOCCC judges first. Please send your request using the instructions on the contacting the IOCCC Judges page.

    Q: What are the grand prize / Best of Show winners?
    A: In 1984-1987, the grand prize winners are:

    Starting from 1988, the entry we liked the most in that year is called "Best of Show". Here are the "Best of Show" entries:
    In 1993, 1994 and 1995 the judges were unable to select a clear overall winner. So to give a nod to the entry that had the highest approval ranking from the judges, they used the following awards: These could be considered the 'better entry' for those years with 1 or more other entries that came in close behind.

    Q: I managed to get entry xyzzy from year 19xx to compile; now it fails to run!
    A: switch(19xx/xyzzy) {


    Q: How did the IOCCC get started?
    A: One day (23 March 1984 to be exact), back Larry Bassel and I (Landon Curt Noll) were working for National Semiconductor's Genix porting group, we were both in our offices trying to fix some very broken code. Larry had been trying to fix a bug in the classic Bourne shell (C code #defined to death to sort of look like Algol) and I had been working on the finger program from early BSD (a bug ridden finger implementation to be sure). We happened to both wander (at the same time) out to the hallway in Building 7C to clear our heads.

    We began to compare notes: ''You won't believe the code I am trying to fix''. And: ''Well you cannot imagine the brain damage level of the code I'm trying to fix''. As well as: ''It more than bad code, the author really had to try to make it this bad!''.

    After a few minutes we wandered back into my office where I posted a flame to net.lang.c inviting people to try and out obfuscate the UN*X source code we had just been working on.

    BTW: I (Landon Curt Noll) had to post this typo correction. Thus began the tradition of putting typos in the contest rules and guidelines ... to make them more obfuscated of course! :-)

    BTW: This posting was made back in the days when AT&T was the evil giant. Now, Microsoft makes AT&T look mild and kind in comparison. :-( (IMHO) ).

    BTW: See the story about the '' Bill Gates'' award. :-)

    OK, back to the story. We (Larry and I) received a number of entries by EMail. When we began to receive messages from outside of the US, Larry and I decided to include International in the name. The 1st IOCCC winners were posted on 17 April 1984.

    There were 4 winners in 1984:
    1. <dis>honorable mention
    2. 3rd place
    3. 2nd place
    4. 1st place
    BTW: The <dis>honorable mention wished to remain anonymous. While many have asked who it was, we have continued to follow the author's wish to remain anonymous. A few years ago, we asked the author if they still wanted to remain anonymous. They said: ''Yes, I want to keep my anonymity. But you can tell them that I am a well known for my connection to the C language"''. It was not until 2001 that another anonymous entry received an award.

    BTW: The 1984 winner remains one of my (Landon Curt Noll) all time favorites.

    The name used in the posting of the 1st IOCCC winner posting was International Obfuscated C Code Contest or IOCCC for short.

    The posting said ''1st annual'', so in 1985 we held the 2nd IOCCC contest and the tradition continues as the longest running contest on the Internet.

    P.S. Part of the inspiration for making the IOCCC a contest goes to the Bulwer-Lytton fiction contest.

    P^2.S. See the overall README for more details.

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    © Copyright 1984-2020, Leo Broukhis, Simon Cooper, Landon Curt Noll - All rights reserved
    This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.