Re: [MiNT] Calling gemdos function from Interruption

[Evan Langlois <Evan@CoolRunningConcepts.com>]

On Tue, 2005-10-11 at 12:40 +0200, Ingo Schmidt wrote:

> I can call GEMDOS calls within a signal handler. And in XaAES I can
> even make AES calls from within a signal handler.
> 
> But a signal handler is context dependant. The OS knows to which
> process a signal handler belongs.

My first reaction was "why?", since, in Unix, I'm used to simply setting
a flag or something in a signal handler, and then handling the signal
from the process's main event loop, keeping the signal handler as small
as possible.

However, with the Atari, most event loops are simply just a call to
evnt_multi(), which doesn't handle file handle events.  Being able to
call GEMDOS within the signal handler could possibly be quite useful as
you could have a background thread handling file/pipe/network IO and
simply send a signal to the parent AES process to tell it to update its
display.

If evnt_multi was the last OS call made when a signal handler fires,
does evnt_multi() return with some error code to say it was interrupted
by a signal (making it possible to use the "set a flag and handle it in
the main event loop method) or does the evnt_multi() continue to wait
for AES events (meaning you'd have to handle the signal completely
within the signal handler, and being able to call GEMDOS and AES would
be incredibly useful!).

-- Evan