Re: encapsulating directory operations

"Kaz Kylheku" <643-408-1753@kylheku.com> wrote in message
news:20250520163755.523@kylheku.com...

On 2025-05-20, Paul Edwards <mutazilah@gmail.com> wrote:

"Paul Edwards" <mutazilah@gmail.com> wrote in message
news:100j09o$2f04b$1@dont-email.me...
>

Manipulating directories is not as important as manipulating
files. The C90 people didn't leave out file manipulation (I
think the ISO Pascal people left it out, at least originally).

>
Actually, I think it was program paramaters that weren't
specified.
>
But again - maybe it is C90 that was wrong to specify argc
and argv and the Pascal people got it right.
>
That depends on the philosophy of language standards.
>
And I am not personally familiar with the philosophy of
language standards.

>
ANSI C was codifying a lot of existing practices.
>
C programs starting with a main() function which takes argc and argv was
in this category.  It came from Unix, and C implementations on other
platforms imitated that.
>
C appeared as the systems programming language of Unix.
C on Unix had a way to process directories via library
functions.
>
Implementors of C on other systems choose to implement some functions
from Unix, and not others. They didn't implement the directory-related
ones, rendering them nonportable, and unsuitable for standardizing
into the language.

There was a reason they weren't implemented.

Probably the same reason they weren't in K&R C either.

Ritchie had the floor to himself. HE chose not to implement it.
Because directories don't really exist everywhere.

But - they sort of do. The concept is - or can be - there.

From my understanding, C and Unix standardization were separate but
somewhat coordinated efforts. Unix things that didn't get into C were
standardized by the emerging Unix standard.
>
Today, if I want a program tha tneeds to walk directories, I use the
POSIX C library. It is widely implemented. The program won't run
absolutely everywhere, but it will run on many embedded systems,
as well as supercomputers, and everything in between.

You have stated the problem. I want to run on some
definition of "absolutely everywhere" that is different
from "many systems".

That's why I'm still on C90, for that "absolutely everywhere",
and now proposing a slight change so that "absolutely
everywhere" is still technically possible. Even on standard MVS.

BFN. Paul.