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Message-Id: <201610282045.u9SKjLl2020432@ip-10-146-233-104.ec2.internal>
Date: Fri, 28 Oct 2016 20:45:21 +0000
From: "Jim Apple (Code Review)" <gerrit@cloudera.org>
To: Tim Armstrong <tarmstrong@cloudera.com>, impala-cr@cloudera.com,
        reviews@impala.incubator.apache.org
CC: Dan Hecht <dhecht@cloudera.com>, Jim Apple <jbapple@cloudera.com>
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Subject: =?UTF-8?Q?=5BImpala-ASF-CR=5D_IMPALA-3200_=28buffer_pool=29=3A_warn_if_Status_is_ignored=0A?=
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archived-at: Fri, 28 Oct 2016 20:45:34 -0000

Jim Apple has posted comments on this change.

Change subject: IMPALA-3200 (buffer pool): warn if Status is ignored
......................................................................


Patch Set 2:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/4878/2/be/src/bufferpool/buffer-allocator.h
File be/src/bufferpool/buffer-allocator.h:

PS2, Line 38: MUST_USE(Status)
> I guess we'd have to wait for C++17, where in the link Tim sent (http://en.
Good point!

I guess we could pass "c++1z" rather than "c++14", but we might also need to upgrade to a newer gcc in the toolchain:

https://gcc.gnu.org/projects/cxx-status.html#cxx1z

Another idea is to switch to clang for all builds. I tested it, and clang allows this attribute on types:

    struct[[gnu::warn_unused_result]] Foo {
      int bar;
    };

    Foo Baz() { return {11}; }

    int main() {
      Baz();
      const auto qux = Baz();                                                                                       
      return qux.bar;
    }

GCC (4.9.2) warns about using the attribute in the wrong place. Clang (3.8.0-p1) warns about the unused return value from the Baz call on the first line of main.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I8c26e7532b5f2c7fe167accc73179e8b72b192bc
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Jim Apple <jbapple@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: Yes