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From: Nick Desaulniers <ndesaulniers@google.com>
To: bvanassche@acm.org
Cc: jgg@ziepe.ca, Nathan Chancellor <natechancellor@gmail.com>,
	dledford@redhat.com, linux-rdma@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] IB/mlx4: Avoid implicit enumerated type conversion
Date: Thu, 27 Sep 2018 15:42:24 -0700	[thread overview]
Message-ID: <CAKwvOd=qNZsfSFJUFZqBbSYt4T_T7TudohzhTqpigvDAHek78A@mail.gmail.com> (raw)
In-Reply-To: <1538087622.226558.8.camel@acm.org>

On Thu, Sep 27, 2018 at 3:33 PM Bart Van Assche <bvanassche@acm.org> wrote:
>
> On Thu, 2018-09-27 at 16:28 -0600, Jason Gunthorpe wrote:
> > On Thu, Sep 27, 2018 at 01:34:16PM -0700, Nick Desaulniers wrote:
> >
> > > > Neither ib_qp_create_flags nor mlx4_ib_qp_flags have negative values, is
> > > > signedness necessary?
> > >
> > > enums are by default restricted to the range of ints.
> >
> > That's not quite right, the compiler sizes the enum to be able to fit
> > the largest value contained within, today that is int, but if we added
> > 1<<31, then it would become larger.
>
> Hi Jason,
>
> Are you perhaps confusing C and C++? For C++, an enumeration whose underlying
> type is not fixed, the underlying type is an integral type that can represent
> all the enumerator values defined in the enumeration. For C however I think
> that enumeration values are restricted to what fits in an int.
>
> Bart.
>

To quote the sacred texts (ANSIIISO9899-1990):

6.5.2.2 Enumeration specifiers
The expression that defines the value of an enumeration constant shall
be an integral constant
expression that has a value representable as an int.
-- 
Thanks,
~Nick Desaulniers

  reply	other threads:[~2018-09-27 22:42 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-24 19:57 [PATCH] IB/mlx4: Avoid implicit enumerated type conversion Nathan Chancellor
2018-09-24 22:24 ` Nick Desaulniers
2018-09-24 22:27   ` Nathan Chancellor
2018-09-24 22:29     ` Nick Desaulniers
2018-09-25  2:37       ` Jason Gunthorpe
2018-09-27  1:08         ` Nathan Chancellor
2018-09-27  4:48           ` Jason Gunthorpe
2018-09-27 20:13             ` Nick Desaulniers
2018-09-27 20:28               ` Nathan Chancellor
2018-09-27 20:34                 ` Nick Desaulniers
2018-09-27 20:36                   ` Nathan Chancellor
2018-09-27 22:28                   ` Jason Gunthorpe
2018-09-27 22:33                     ` Bart Van Assche
2018-09-27 22:42                       ` Nick Desaulniers [this message]
2018-09-27 22:58                         ` Jason Gunthorpe
2018-09-27 23:08                           ` Bart Van Assche
2018-09-28  0:55                           ` Nick Desaulniers
2018-09-28  3:04                             ` Jason Gunthorpe
2018-09-27 20:43 ` [PATCH v2] " Nathan Chancellor
2018-09-27 20:53   ` Nick Desaulniers
2018-10-03 22:35 ` [PATCH] " Jason Gunthorpe
2018-10-03 22:53   ` Nick Desaulniers
2018-10-03 23:01     ` Jason Gunthorpe
2018-10-03 23:09       ` Nick Desaulniers

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