Re: OT: Windows (Was: Re: Open Source does not mean easily

In article <vljg72$28nj0$1@dont-email.me>,  <Muttley@DastardlyHQ.org> wrote:

On Tue, 7 Jan 2025 14:13:29 -0000 (UTC)
cross@spitfire.i.gajendra.net (Dan Cross) wibbled:

In article <vlioum$24bqm$1@dont-email.me>,  <Muttley@DastardlyHQ.org> wrote:

On Mon, 6 Jan 2025 16:39:49 -0000 (UTC)
Thats not the same as the program itself being asynch.

>
Isn't it?  The point is that the program kicks off multiple

>
Not, it isn't. Using operating system facilities is standard programming, its
not asych programming whereby the program execution will be automatically
be diverted when an operation completes.
>

Thats not proper asych, its still sequential. Proper asynch is when the
program execution path is directly modified by external events. Otherwise
you could claim simply using the standard file I/O system is asynchronous
programming as there's no guarantee that any data has been written to the

disk

before write(), fprintf() etc return.

>
This is conflating multiple things.  Most IO operations dealing
with the actual hardware _are_ asynchronous (this is what
McIlroy meant in the quote I posted earlier).  The system call
interface gives the program the illusion of those happening
sequentially, but that's not how the devices really work.

>
And? By your definition its still asynchronous programming.

In the kernel, it sure is.  Unix programmers have been writing
asynchronous programs (using e.g. `fork`) since 1970.

Sure, but as I've said before, signals should only set flags to be processed
later.

>
You said that, but that flies in the face of 50 years of
evidence to the contrary and the letter of the standard.  This

>
Please don't just make stuff up.

Hmm.  I wonder what shell you use, if you use Unix at all.

Here for example is the signal handler for SIGINT in bash:
https://git.savannah.gnu.org/cgit/bash.git/tree/sig.c?h=devel#n691

You'll notice that it's rather more complex than just "set a
flag or `wait`.

Here's the handler in `zsh`:
https://github.com/zsh-users/zsh/blob/263659acb73d0222e641dfd8d37e48e96582de02/Src/signals.c#L399

You'll again notice that it does rather more than just "set a
flag or wait."

Here's the SIGWINCH handler for good 'ol `script` from
OpenBSD:
https://github.com/openbsd/src/blob/6d253f95424ee0054c798f493d12377911cd3668/usr.bin/script/script.c#L224

Wow, that one does ioctl's modifying PTY state and signals an
entire process group.  That's definitely a bit more than just
"setting a flag or wait."

Here's an example from Postgres:
https://github.com/postgres/postgres/blob/5b291d1c9c09d75982c3270bfa61d4e822087b6a/src/backend/storage/ipc/latch.c#L2269

Wow, that one writes to a pipe.  Definitely a bit more than just
"setting a flag or wait."

Those are just a few examples.  If one cares to look, one will
find many more in non-trivial programs used in production daily.

- Dan C.