RE: [GD-General] Overhead of RTTI

[Grills, J. <jg...@so...>]

I think it somewhat depends on your compiler.

Two of the larger profile spikes in a Win32 compile (using MSVC 6) of one of
our applications right now are caused by excessive use of dynamic_cast.  I
spent some time looking at the code dynamic_cast created, and it's ugly.  It
even does string compares internally, which is completely gross.  For places
where performance matters, we are adding a "virtual Derived *
asDerivedClass()" function which returns NULL in the base class and "this"
in the Derived class.  Tracking down inappropriate frequent callers of
dynamic_cast can be pretty tedious as well.

GCC's code gen for this stuff is apparently a fair bit better.

j


-----Original Message-----
From: Tom Forsyth [mailto:to...@mu...]
Sent: Tuesday, December 24, 2002 7:02 AM
To: gam...@li...
Subject: RE: [GD-General] Overhead of RTTI


It's usually far quicker and easier to code it yourself with a few helper
functions, unless you actually need the full madness of RTTI.

Tom Forsyth - Muckyfoot bloke and Microsoft MVP.

This email is the product of your deranged imagination,
and does not in any way imply existence of the author.

> -----Original Message-----
> From: Adrian Cearnau [mailto:ce...@ce...]
> Sent: 24 December 2002 12:50
> To: gam...@li...
> Subject: [GD-General] Overhead of RTTI
> 
> 
> Hey everyone and merry X-Mas,
> 
> I'd like to know what the realistic overhead of enabling RTTI in a C++
> project is. Any opinions are welcome.
> 
> Thank you,
> Adrian 'cearny' Cearnau