Scott Wood scottwood at freescale.com
Fri May 2 02:14:51 EST 2008

On Thu, May 01, 2008 at 08:17:07AM -0500, Kumar Gala wrote:
> On May 1, 2008, at 3:24 AM, Paul Mackerras wrote:
> >The most common cases are (a) something that ultimately generates
> >input on a tty (e.g. a character arriving on a serial port) and that
> >input turns out to be a ^C or similar, or (b) something that signals
> >I/O completion and the program doing the I/O has requested
> >notification by a SIGIO.  But in general any driver code can send a
> >signal to userspace if it wants.

And, of course, SIGALRM and similar timer mechanisms.

> ok.  Was just wondering how the async exception know that the signal  
> it wanted to send belonged to the particular process that is running.   
> But I guess there are cases that the signal is really intended for who  
> ever is currently running?

No, it knows based on its own data structures who it's intended for --
and sometimes that happens to be the currently running process.


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