Re: 80286 protected mode

Stephen Fuld <sfuld@alumni.cmu.edu.invalid> writes:

On 10/9/2024 1:20 PM, David Brown wrote:
>

There are lots of parts of the standard C library that cannot be
written completely in portable standard C.  (How would you write
a function that handles files?  You need non-portable OS calls.)
That's why these things are in the standard library in the first
place.

>
I agree with everything you say up until the last sentence.  There
are several languages, mostly older ones like Fortran and COBOL,
where the file handling/I/O are defined portably within the
language proper, not in a separate library.  It just moves the
non-portable stuff from the library writer (as in C) to the
compiler writer (as in Fortran, COBOL, etc.)

What I think you mean is that I/O and file handling are defined as
part of the language rather than being written in the language.
Assuming that's true, what you're saying is not at odds with what
David said.  I/O and so forth cannot be written in unaugmented
standard C without changing the language.  Given the language as
it is, these things must be put in the standard library, because
they cannot be provided in the existing language.

There is an advantage to the C approach of separating out some
facilities and supplying them only in the standard library.  In
particular, it makes for a very clean distinction between two
kinds of implementation, what the C standard calls a freestanding
implementation (which excludes most of the library) and a hosted
implementation (which includes the whole library).  This facility
is what allows C to run easily on very small processors, because
there is no overhead for non-essential language features.  That is
not to say such things couldn't be arranged for Fortran or COBOL,
but it would be harder, because those languages are not designed
to be separable.