[int_19h]

The amusing thing about it is that C does not guarantee that EOF is out-of-band!

ISO C says that char must be at least 8 bits, and that int must be at least 16. It is entirely legal to have an implementation that has 16-bit signed char and sizeof(int)==1. In which case -1 is a valid char, and there's no way to distinguish between reading it and getting EOF from getchar().

[kstenerud]

... which is why no system ever implements things this way. There are many portions of the C spec that can be ignored.

Large swaths of the C standard were built during the heyday of computer design, when you had all sorts of wacky sizes, behaviors and abstractions. Lots of "undefined behavior" is effectively deterministic, because all modern computers have converged to do so many things the same way.

[plorkyeran]

TI DSPs with 16-bit char are still being made. It's a niche thing that most people will never need to care about, but it's not just a historical quirk and definitely not "no system ever".

[int_19h]

Then there's SHARC with its 32-bit char.

Do architectures like that have non-freestanding C implementations, though? It's kinda moot if there's no getchar()...