Mail Archives: djgpp-workers/1998/07/22/15:53:34
Charles wrote:
> > > > If you think about using the usual DJGPP RMCBs, then I think they
> > > > *must* be locked, or CWSDPMI will abort your program. Charles, am I
> > > > right here?
> > >
> > > Sorry, I fail to catch the idea, what do you think we must lock and
> > > why?
> >
> > Charles once told me that CWSDPMI imposes a limitation on RMCBs, for
> > safety reasons, and the upshot is that you must lock every code and data
> > that is called by an RMCB. But I'm not sure I got it right, so I will
> > wait for Charles to give the definitive answer.
>
> If a RMCB comes into CWSDPMI ... you are never sure what state DOS is in.
> A mouse call back may have interrupted DOS - and if you need to page fault
> you would re-enter DOS, which can destroy your hard disk.
>
> So, if you used the RMCB you would have to lock the buffers that you take
> bytes out of and the code, but this would be fairly small and localized.
But we want to make it: DJGPP program B calls a real mode function,
the real mode funtion is a RMCB that was created by djgpp program A
so the execution jumps to program A.
As program B is in protected mode and in normal execution (not inside
an ISR) we are shure that DOS isn't busy.
That's our case. Now Eli question is if we need to lock the code just
because CWSDPMI will check it even when DOS isn't busy.
> BTW - with my travel schedule it may sometimes take up to a week before I
> can reply to these things...
Ok.
Greetings, SET
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