SA_INTERRUPT

["Bradley D. LaRonde" <brad@ltc.com>]

What is the current wisdom on SA_INTERRUPT?

A comment in signal.h about it says "dummy -- ignored".  Elsewhere it says
that "SA_INTERRUPT is a no-op left for historical reasons".

That certainly doesn't seem to be the case in irq.c.  It appears to be used
like this: if SA_INTERRUPT isn't set, enable interrupts during interrupt
handling.

So what is this flag for?  How, when, and why should it be used?

Thanks.

Regards,
Brad