The 29th International Obfuscated C Code Contest (IOCCC) 2025 Winners
Points and comments are a snapshot, not live.
The 29th IOCCC announced 22 winning entries, with record submission volume and quality following a four-year hiatus.
The International Obfuscated C Code Contest (IOCCC29) received near-historic submission volumes and quality. Winners include a GameBoy emulator by Nick Craig-Wood, a Subleq computer by cable, a patch/diff quine by Yusuke Endoh, and a Forth interpreter. Three authors achieved hat tricks: Endoh, Craig-Wood, and Don Yang each won three awards. The contest saw its first winner from Taiwan (jingp49). The judges documented the entire closing and judging process, improving future contest procedures. IOCCC30 is planned to open late 2026 and close in Q1 2027. Winning entries include novelties like a GameBoy emulator shaped like a GameBoy, an ocean sound generator, and a quasi-rogue-like game.
What commenters are saying
The thread's dominant concern was website usability: the IOCCC site itself is obfuscated, making it hard to find C sources and understand what the contest is. A top comment praised the GameBoy emulator entry, noting the author Nick Craig-Wood created rclone and that the code visually resembles a GameBoy. Craig-Wood replied with technical details: the entry required 100 hours to compress a 6000-character emulator into the 2503-character limit, involving abuse of C features and ISO 646 operator tricks. A secondary thread discussed LLM participation; the FAQ explicitly permits AI tools. One commenter noted another favorite entry (cable's 366-byte Subleq emulator) and linked a video presentation.