Re: Installing a C function into the IDT

The Prisoner wrote:
> Hey-
> 
> I was reading about interrupts, and I got to thinking it would be a real
> neat thing to use interrupts for program-wide exception handling. What I
> haven't been able to find is a clear guide or example program for how to
> install a C function into the IDT. And what happens about passing
> arguments?
> 
> I'd like to have something like this:
> 
> void malloc_failure();
> 
> Say I install this as interrupt slot 42, then I can do:
> 
> if(!(p=(int*)malloc(1000*4))) // array of 1000 ints
>   __asm__ ("int $0x42");
> 
> Is there any reason for this not to work? How do I set up the
> interrupts? Would I need root privelidges to do that?
> 
Interrupts and their handling are beyond standard C.

Where they are used, interrupts handlers (like signal handlers on a Unix
like system) generally have their own context, they are synchronous.
There is little a handler can do to influence the main line code unless
that code polls some shared state.  In other words even if you could use
interrupts for exceptions, the code would still have to check to see if
one had fired.  So you gain nothing.

-- 
Ian Collins.