Gnus99 [OFFICIAL]

The "gnu99" dialect, used by the GNU Compiler Collection (GCC), combines the ISO C99 standard with specific GNU extensions like nested functions, zero-length arrays, and binary constants. It serves as a bridge for system-level programming and older Linux kernel modules, although modern GCC versions have largely transitioned to defaults like "gnu11" or "gnu17". You can read the full documentation at GCC .