:: Re: [DNG] simple-netaid from scratc…
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著者: Steve Litt
日付:  
To: dng
題目: Re: [DNG] simple-netaid from scratch
On Tue, 11 Jun 2019 22:07:22 +0100 (BST)
Jim Jackson <jj@???> wrote:

> On Tue, 11 Jun 2019, Steve Litt wrote:
>
> > On Mon, 10 Jun 2019 15:01:53 +0100
> > s@po <tuxd3v@???> wrote:
> >
> > > On Mon, 10 Jun 2019 13:34:54 +0100 (BST)
> > > Jim Jackson <jj@???> wrote:
> > >
> > > >
> > > > sizeof()  is calculated by the compiler, not at run time. The
> > > > code generated would be the same.    

> > >
> > > Hello Jim,
> > > Indeed it his, my point was only a observation, that if size is
> > > fixed, no need to calculate it at compile time, the preprocessor
> > > can solve that with a macro.. The code generated will be indeed
> > > the same. Only was a observation ;)
> >
> > I vote for leaving it as a function.
> >
> > What would be gained by making it a macro? A microsecond? What are
> > the bottlenecks of the software? Are keyboard or mouse input
> > involved?
> >
> > If these sizeof() calls are deep in a tight nested loop, by all
> > means make them into a macro. Otherwise, why give up the simplicity
> > of a function for the sometimes edge case weirdness of a macro?
>
> I do wish people would read. Those sizeof()'s are not executable
> functions, they are calculated by the compiler at compile time into
> their fixed numbers and inserted into the code as fixed numbers, just
> as a macro would! There is no difference at runtime. The code
> generated would be identical.
>
> There is no execution penalty to using sizeof()!


Then sizeof() is perfect for the job.

SteveT

Steve Litt
June 2019 featured book: Thriving in Tough Times
http://www.troubleshooters.com/thrive