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From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: "Wodkowski, PawelX" <pawelx.wodkowski@intel.com>,
	Thomas Monjalon <thomas.monjalon@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] error: value computed is not used
Date: Mon, 15 Dec 2014 16:35:24 +0000
Message-ID: <2601191342CEEE43887BDE71AB977258213C0DBE@IRSMSX105.ger.corp.intel.com> (raw)
In-Reply-To: <F6F2A6264E145F47A18AB6DF8E87425D12B79FC6@IRSMSX102.ger.corp.intel.com>



> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wodkowski, PawelX
> Sent: Monday, December 15, 2014 3:44 PM
> To: Thomas Monjalon
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] error: value computed is not used
> 
> > > > > And something like this?
> > > > >
> > > > >  #define rte_memcpy(dst, src, n)              \
> > > > > -	((__builtin_constant_p(n)) ?          \
> > > > > +	({ (__builtin_constant_p(n)) ?          \
> > > > >  	memcpy((dst), (src), (n)) :          \
> > > > > -	rte_memcpy_func((dst), (src), (n)))
> > > > > +	rte_memcpy_func((dst), (src), (n)); })
> > > >
> > > > What happens to the returned value after this change?
> > > > ptr = rte_memcpy(dst, src, n) + offset:
> > > >
> > > https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement-Exprs
> > >
> > > Whole expression should be 'void *' type (like *memcpy()) and it should work
> > > as usual (see maxint() example in above link). It is GCC extension.
> >
> > OK nice.
> > I didn't test it on SUSE 11 SP3. I assume you did it?
> I did not tested this, as this was only proposal. I only run build process and it pass.
> Patch proposal will be sent in a while.
> 
> > Please Pawel, could you send a proper patch quickly?
> > If nobody disagree, it'll be merged in RC5 today.
> >
> > > > > Thomas, can you check build with EXTRA_CFLAG='-Wunused-value'.
> > > >
> > > > You mean EXTRA_CFLAGS (with a S).
> > > > It fails in many locations.
> > > > What's your point?
> > >
> > > I am just asking if this is an typo, error or intend to do statements with no
> > effects like bellow.
> > >
> > > ixgbe_common.c:4429:3: error: statement with no effect [-Werror=unused-
> > value]
> > >
> > > 4426:	/* first pull in the header so we know the buffer length */
> > > 4427:	for (bi = 0; bi < dword_len; bi++) {
> > > 4428:		buffer[bi] = IXGBE_READ_REG_ARRAY(hw, IXGBE_FLEX_MNG,
> > bi);
> > > 4429:		IXGBE_LE32_TO_CPUS(&buffer[bi]); // <------ here
> > > 4430	}
> >
> > It's an intent. On big endian CPU, this has an effect.
> >
> 
> If you see something what I am not, please ignore this part but for me this looks like it should be:
> tmp = IXGBE_READ_REG_ARRAY(hw, IXGBE_FLEX_MNG,
> buffer[bi] = IXGBE_LE32_TO_CPUS (tmp);

Yep, same thought here, see my other mail on that subject.
Konstantin

> 
> Pawel

  reply	other threads:[~2014-12-15 16:35 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-08  9:05 Qiu, Michael
2014-12-08 11:00 ` Wodkowski, PawelX
2014-12-08 15:23   ` Qiu, Michael
2014-12-08 15:26     ` Wodkowski, PawelX
2014-12-15 10:54       ` Thomas Monjalon
2014-12-15 11:07         ` [dpdk-dev] [PATCH] enic: fix build on SUSE 11 Thomas Monjalon
2014-12-15 11:27         ` [dpdk-dev] error: value computed is not used Wodkowski, PawelX
2014-12-15 13:26           ` Thomas Monjalon
2014-12-15 13:47             ` Wodkowski, PawelX
2014-12-15 14:16               ` Thomas Monjalon
2014-12-15 15:44                 ` Wodkowski, PawelX
2014-12-15 16:35                   ` Ananyev, Konstantin [this message]
2014-12-15 16:00                 ` Ananyev, Konstantin
2014-12-15 16:40                   ` Thomas Monjalon
2014-12-15 17:03                 ` Jastrzebski, MichalX K
2014-12-16  0:49         ` Qiu, Michael
2014-12-09  9:19 ` Qiu, Michael
2014-12-10  9:26 ` Qiu, Michael

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