[U-Boot] [PATCH] ppc4xx: Add Sequoia RAM-booting target

Wolfgang Denk wd at denx.de
Thu May 7 21:06:27 CEST 2009


Dear Stefan,

in message <200905071739.56301.sr at denx.de> you wrote:
>
> > > Linux kernel btw. Here the macro "__maybe_unsed" is defined to
> > > "__attribute__((unused))".
> >
> > In many cases?  a rgrep on a recent kernel counts 84 incantations, which
> > is not much for the Linux kernel, I believe.
> 
> Perhaps it's quite new to the Linux kernel. I just spotted it the first time a 
> few weeks ago and thought: "What a nice way to remove some of the ugly 
> #ifdef's in U-Boot!". :)

My understanding was that  this  is  (only?)  intended  for  function
declarations  to  silence  warnings  about  unused function arguments
(which may be necessary anyway for  compatible  call  interface  with
other functions that actually need this arg).

> This could be the case. But this could happen to the #ifdef version as well. 
> That the #ifdef'ed variable declaration stays in the code after removing the 
> code referencing the variables.

No. In this case the compiler will issue warnings abouit "unused
variable".

Best regards,

Wolfgang Denk

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