> I've always wondered at the motivatons of the various string routines in C

This idiom:

    char hostname[20];
    ...
    strncpy( hostname, input, 20 );
    hostname[19]=0;

I've always assumed that the n in strncpy was meant to signify a max length N. Now I'm wondering if it might have stood for NUL padding.

Technically strncpy was invented to interact with null-padded fixed-size strings in general. We’ve mostly (though not entirely) moved away from them but fixed-size strings used to be very common. You can see them all over old file formats still.

It’s also horrible because each project ends up reinventing their own abstractions or solutions for dealing with common things.

Destroys a lot of opportunity for code reuse / integration. Especially within a company.

Alternatively their code base remains a steaming pile of crap riddled with vulnerabilities.