[dpdk-dev] [PATCH 0/5] remove usage of register keyword in C

Stephen Hemminger stephen at networkplumber.org
Tue Jul 31 20:07:37 CEST 2018


On Tue, 31 Jul 2018 18:48:40 +0200
Adrien Mazarguil <adrien.mazarguil at 6wind.com> wrote:

> On Tue, Jul 31, 2018 at 09:30:54AM -0700, Stephen Hemminger wrote:
> > Declaring variables as register in C is a leftover from an earlier
> > era (like cassette tape decks in cars).  
> 
> I don't agree here. It's a hint for compilers and developers that the
> address of such variables won't be needed (and cannot be taken) to enable
> whatever optimizations are possible knowing this.
> 
> Somewhat like inline functions, it's not a forced optimization, just a
> useful hint that shouldn't hurt if used wisely.
> 
> Besides, cassette decks are not dead yet :)

If you look at the code, that is not how register is being used (ie. don't take
address of this). It seems like an attempt at optimization.


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