From mboxrd@z Thu Jan  1 00:00:00 1970
From: Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: Re: Build is broken in dpdk-next-net
Date: Fri, 30 Mar 2018 15:27:55 +0200
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Cc: Ferruh Yigit <ferruh.yigit@intel.com>,
 Thomas Monjalon <thomas@monjalon.net>,
 Tonghao Zhang <xiangxia.m.yue@gmail.com>
To: Andrew Rybchenko <arybchenko@solarflare.com>, "dev@dpdk.org" <dev@dpdk.org>
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Hi Andrew,

On 03/30/2018 03:18 PM, Andrew Rybchenko wrote:
> Hi all,
> 
> Build is broken in dpdk-next-net for me on Ubuntu 16.04.4:
> 
> lib/librte_vhost/fd_man.c: In function ‘fdset_pipe_read_cb’:
> lib/librte_vhost/fd_man.c:284:2: error: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Werror=unused-result]
>    read(readfd, charbuf, sizeof(charbuf));
>    ^
> lib/librte_vhost/fd_man.c: In function ‘fdset_pipe_notify’:
> lib/librte_vhost/fd_man.c:324:2: error: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Werror=unused-result]
>    write(fdset->u.writefd, "1", 1);
>    ^
> 
> $ gcc --version
> gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609

Thanks for reporting, I don't catch it with my Fedora build system:
$ gcc --version
gcc (GCC) 7.3.1 20180303 (Red Hat 7.3.1-5)

> 
> As I understand it is broken in ad94ade905454401b705be9e06b19e54a1c78148
> vhost: add pipe event for optimizing negotiating

I confirm it is this patch.

Xiangxia, can you provide a fix please?

Ferruh, how do you want to proceed?
Would you revert it?

Thanks,
Maxime
> Andrew.
>