[Info-vax] C limitations, was: Re: VMS process communication

[Dan Cross]

In article <u260ak$brdi$1 at dont-email.me>,
Arne Vajhøj  <arne at vajhoej.dk> wrote:
>On 4/24/2023 8:59 AM, Dan Cross wrote:
>> In article <kam0vhFq0fdU11 at mid.individual.net>,
>>> Mostly stuff from the comp.sources groups.  Very little of it was
>>> portable.  Even with a lot of massaging.  But the charset values
>>> was the biggest killer because so many programs assumed 0-127 as
>>> ordinal value of the ASCII charset.
>> 
>> I can believe that, but I'd imagine it was less the use of
>> individual code-points as a general assumption that the high-bit
>> was clear, and that thus one could use a char to index a table
>> with only 128 entries or something: things like that still trip
>> up programmers, even in our modern, almost always ASCII or
>> UTF-8, world (indeed, this used to be a source of frustration
>> for using the `is*` family, as they did table lookups: one had
>> to be careful to use `isascii` first before blinding applying
>> them).
>
>The is* functions take an int and are required to accept
>values that can be stuffed into an unsigned char (plus value
>of EOF macro). An is* function using a 128 entry table is broken
>on a system with an >7 bit execution char set.
>
>The isascii function is not in the C standard but only in the
>POSIX standard (The Open Group Base Specifications).

Note the context.  We're discuss pre-standard C.

	- Dan C.