It's indeed a weird thing. It should have been an easy addition to the standard library. But instead people either pass around pointer/length pairs all the time

It's indeed a weird thing. It should have been an easy addition to the standard library. But instead people either pass around pointer/length pairs all the time - or even worse: They rely on null-terminated strings / arrays. I had discussions with people who claimed that null terminated strings are the only idiomatic thing to do in C - because that is how C does strings. They assumed that since the standard library only provided methods which acted on those kinds of strings it was a preferred way to do things. Even though that is a lot less efficient than the string/array types that other languages use as defaults.