gamedevlists-windows

RE: [GD-Windows] R: exception handling

[Daniel V. <Dan...@ep...>]

> A try/catch block usually has zero performance impact until and=20
> unless you actually throw an exception.=20

Exception handling code can significantly increase the size of the stack
frame and lead to quite some increase in executable size so you really
don't want to do it for inlined functions that get called a lot.

Having said that, all Unreal games shipped with a try/ catch block for
almost all non performance critical functions, adding ~1 MByte to the
executable and costing ~5% performance.

-- Daniel, Epic Games Inc.

RE: [GD-Windows] R: exception handling

[Jon W. <hp...@mi...>]

> Exception handling code can significantly increase the size of the stack
> frame and lead to quite some increase in executable size so you really
> don't want to do it for inlined functions that get called a lot.

I know that very old implementations of C++ would add to the stack (to
store basically a jmp_buf) when doing a try. However, I'm under the
impression that all modern compilers use zero overhead exceptions, where
the only overhead happens if you actually throw -- plus, as we agree, the
tables in the executable on disk. If you don't have a goof VM system,
those can hurt a lot :-)

Hmm. Everything I know about exception implementation actually comes from
my CodeWarrior days plus a bit of GCC. Could it be that MSDEV has
specialness in this area?

I just disassembled a MSDEV 7.1 compiled program, and it appears that it
actually puts all functions with exception information into a special list,
so they don't actually implement zero-overhead exceptions. Curious. Thanks
for the heads up!

Cheers,

			/ h+