Re: exceptions and threads---a survival tactic!

[Joe Buck <jbuck at synopsys dot com>]

Kaz Kylheku wrote:
> > The potential bottleneck should not be a worry since
> > in well designed programs (IMHO), exception handling is
> > an infrequent occurence for, well, ``exceptional'' events.

Branko Cibej writes:
> You should look at some of the discussions in the comp.lang.c++.moderated
> archive :-) You'll find that opinions about that vary widely.
> 
> The fact is, with properly implemented exception-handling code that *does*
> care about runtime overhead, you can write much faster code by using EH for
> flow control than by the traditional "if (foo) bar(); else baz();" method.

Yes, and this can be even more true in Java.  The March '98 issue of Byte
has a piece by David Orchard entitled "Better Performance With Exceptions
in Java".  He finds that, for very large arrays, 

try {
	for (int i = 0; ; i++) {
		anInt[i] = i;
	}
}
catch (ArrayIndexOutOfBoundsException e) {}

is 30-40% faster on JDK 1.1.3 (Sun's Windows version) than the traditional

	for (int i = 0; i < ARRAY_SIZE; i++) {
		anInt[i] = i;
	}

(I suspect, though, that this is because there is a range check on each
array access in Java, so the traditional code does the same test twice).