"But my point was that a programmer should understand the standard"
But suppose the standard does not evidently aim to be understood, in the
generally understood meaning of "understood",
or there are more words in the standard than will ever appear in the
programmer's own programs?
Worse! "Standard" doesn't imply a fixed point ("oh, that syntax/semantics
is so last year!").
I think looking into memset and deciding it's not worthwhile calling is
perhaps overly enthusiastic.
Actually, it's wrong, because it overlooks the side-effect, and an
optimiser for a language with side-effects
should take that into account.
