In my experience working on a wide range of systems software—including device drivers, Linux, other operating systems, and high-performance computing (HPC) libraries—I've encountered a recurring pattern of C programming habits that feel like relics of an earlier era. These coding styles, often found in legacy codebases or written by seasoned engineers who have been using C since the 1980s, exhibit a mix of outdated conventions, compiler-era quirks, and practices that are either unnecessarily cryptic or outright hazardous. After seeing these patterns repeatedly, I started referring to it as Boomer C.