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From: David Marchand <david.marchand@redhat.com>
To: Thomas Monjalon <thomas@monjalon.net>, Eli Britstein <elibr@nvidia.com>
Cc: dev <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] eal: fix build with conflicting libc variable memory_order
Date: Thu, 15 Oct 2020 09:12:56 +0200	[thread overview]
Message-ID: <CAJFAV8w8Z2ffLduTN70DVxJ-RWVLhY7my2Azhg+AfkzG7A4PMQ@mail.gmail.com> (raw)
In-Reply-To: <1634944.yJlA45dGKM@thomas>

On Thu, Oct 15, 2020 at 1:16 AM Thomas Monjalon <thomas@monjalon.net> wrote:
>
> 14/10/2020 08:19, Eli Britstein:
> > The cited commit introduced functions with 'int memory_order' argument.
> > The C11 standard section 7.17.1.4 defines 'memory_order' as the
> > "enumerated type whose enumerators identify memory ordering constraints".
> > Applications that use the standard enum (includes stdatomic.h), will
> > fail compilation with:

Simply including stdatomic.h does not trigger the problem.
Can you rework this commitlog with below info?

> > error: declaration of 'memory_order' shadows a global declaration
> >     [-Werror=shadow]
> >      rte_atomic_thread_fence(int memory_order)
> > Fix it by changing the argument name 'memory_order' to 'memorder'.
>
> Not clear why it builds fine with most compilers,

I can reproduce in two cases:
- with a gcc that provides a stdatomic.h header + passing
-Wsystem-headers in the CFLAGS,
- with a compiler that does not provide stdatomic.h and you redefine
memory_order in your code (like OVS does),


> but the fix does not hurt.

Otherwise, yes, lgtm.


> > Fixes: 672a15056380 ("eal: add wrapper for C11 atomic thread fence")
>
> A blank line should be inserted here.
>
> > Signed-off-by: Eli Britstein <elibr@nvidia.com>
>
> Acked-by: Thomas Monjalon <thomas@monjalon.net>

Acked-by: David Marchand <david.marchand@redhat.com>


-- 
David Marchand


      reply	other threads:[~2020-10-15  7:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-14  6:19 Eli Britstein
2020-10-14 13:34 ` Asaf Penso
2020-10-14 23:16 ` Thomas Monjalon
2020-10-15  7:12   ` David Marchand [this message]

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