Re: [PATCH] eal/ppc: undefine AltiVec keyword vector

[Tyler Retzlaff <roretzla@linux.microsoft.com>]

On Wed, May 25, 2022 at 07:02:52PM +0100, Ray Kinsella wrote:
> 
> Thomas Monjalon <thomas@monjalon.net> writes:
> 
> > 25/05/2022 13:48, Ray Kinsella:
> >> 
> >> Thomas Monjalon <thomas@monjalon.net> writes:
> >> 
> >> > The AltiVec header file is defining "vector", except in C++ build.
> >> > The keyword "vector" may conflict easily.
> >> > As a rule, it is better to use the alternative keyword "__vector".
> >> >
> >> > The DPDK header file rte_altivec.h takes care of undefining "vector",
> >> > so the applications and dependencies are free to define the name "vector".
> >> >
> >> > This is a compatibility breakage for applications which were using
> >> > the keyword "vector" for its AltiVec meaning.
> >> >
> >> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> >> > ---
> >> >  doc/guides/rel_notes/release_22_07.rst | 5 +++++
> >> >  lib/eal/ppc/include/rte_altivec.h      | 7 +++++++
> >> >  2 files changed, 12 insertions(+)
> >> >
> >> 
> >> Acked-by: Ray Kinsella <mdr@ashroe.eu>
> >
> > Just to make sure, we are all OK to break compatibility of rte_altivec.h?
> > It means the keyword vector is not available anymore with this #include.
> > Please confirm it is OK to merge in DPDK 22.07.
> 
> I did think about it yes ;-).
> I can't see how it would break the ABI in the short term.
> And it makes sense to preclude this keyword in the long term.
> 
> So I ack'ed - did I miss something?

Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>

double ack, impact of break is understood as follows.

* this is not an issue with abi it is an issue with api.
* the break will cause a compile failure, the action to resolve is to
  replace vector with __vector.

> 
> 
> -- 
> Regards, Ray K