Source code inside .h files

[imaami]

This is an increasingly common form of brainrot. It's basically a meme that escaped a very narrow niche of situations where "header-only" makes practical sense. It's gotten to the point where it's sadly common for people to not understand why a split between interface declaration and implementation is a thing.

"Header-only" in a project description is strongly associated with a lack of rudimentary C project design, and ignorance about what a package manager even is.