Re: speed of Obj-C vs. C++(slightly OT)

[Philippe C . D . Robert]

On Tuesday, April 22, 2003, at 11:12 AM, Graham Lee wrote:
> Jim McLoughlin wrote:
> > On Tuesday, April 22, 2003, at 01:36 AM, Dirk Theisen wrote:
> > > You can always include C libraries for maximum speed.
> > > AFAIK, some computational finance libs are in plain C anyway so you 
> > > can get by with using C for the computations and ObjC for the rest 
> > > (where message passing times do not matter).
> > Thanks for the response.  I realized after posting that it all 
> > depends on how you split things up between C/C++ or C/Obj-C. I guess 
> > my question is that, assuming these ratios are equal, which is >> faster.
> C++.  The reason is that C++ is *not* an Object-Oriented language, it 
> has structs and it has functions.  When you have a method in C++ (such 
> as myClass.doSomething(withThis);), the method is

This is a wrong statement (but please do not start a flame war here 
about what is OOP and what is not!). There is not just one definition 
of what OO is - by the way ObjC also has structs and also supports 
functions. C++ completely supports OO programming although it is not 
based on SmallTalk principles. Moreover OO by itself does not imply 
"being slow". And yes, C++ function calls are faster than ObjC method 
invocation, now how much this affects application performances is a 
completely different question, of course.

>  resolved at *compile time* into a standard ol' C function call, which 
> probably takes all of around four cycles for a function that takes no 
> arguments, and uses about the same number to leave if the function 
> returns void.

This is not true either. Non-virtual functions are resolved at compile 
time while virtual functions are resolved at runtime using a virtual 
table!

-Phil
--
Philippe C.D. Robert
http://www.nice.ch/~phip