C is a little older than namespacing and object orientation. C++ wasn’t even a glimmer in Bjarne’s eye when these conventions were laid down.

And yes, having to google it is part of the design. Originally C programmers would have had to read actual manuals about this stuff. Once you learn the names you don’t really forget so it works well enough even now for ubiquitous standard library functions.

And yet, C was an ergonomic revelation to programmers of the time. Now it’s the arcane grandpa that most youngsters don’t put up with.