This is the mail archive of the gcc-help@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Understanding Macro Pre-processor


2007/9/21, Dave Korn <dave.korn@artimi.com>:
> On 20 September 2007 20:44, Bruno Moreira Guedes wrote:
>
> > Bu I've been made some tests... By example... A macro:
> >
> > #define mul(X,Y) (X*Y)
> >
> >
> > It makes the processing faster...
>
>   Your test methodology is broken.
>
> > But... Why executing that a milion of times is faster than using the
> > simple a*b itself???
>
>   It isn't.
>
> > It really happens?
>
>   It doesn't.
>
> > Why?
>
>   Because you did one timing run when your system was under very heavy load of
> background tasks and the other when it was under very light load, most likely.
>

So, my old concept(it's just replace the source text) is right??
Then, the ones who frequently insists that using macros makes part of
the processing at compile-time is really wrong?

Going out of the original question, does someone recommend me a good
doc about how to optimize my programs, making it run fast.

>
>     cheers,
>       DaveK
> --
> Can't think of a witty .sigline today....
>
>


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]