Re: add __attribute__((noreturn)) to suppress a waring

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From: Itagaki Takahiro <itagaki(dot)takahiro(at)gmail(dot)com>
To: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: add __attribute__((noreturn)) to suppress a waring
Date: 2011-01-24 01:42:35
Message-ID: AANLkTikvi3m7RKOtHP0ctSdspSfmc-75fmWv79GYLM57@mail.gmail.com
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I found the following warning with Fedora 14 / gcc 4.5.1.
----
pg_backup_archiver.c: In function ‘_discoverArchiveFormat’:
pg_backup_archiver.c:1736:11: warning: ‘fh’ may be used uninitialized
in this function
----
To suppress it, I'm thinking to add noreturn to die_horribly().
Any objections? Another solution might be adding a dummy assignment
after calls of die_horribly().

--
Itagaki Takahiro

Attachment Content-Type Size
noreturn.diff application/octet-stream 1.6 KB

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Itagaki Takahiro <itagaki(dot)takahiro(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: add __attribute__((noreturn)) to suppress a waring
Date: 2011-01-24 06:32:51
Message-ID: 4D3D1D13.3040509@enterprisedb.com
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On 24.01.2011 03:42, Itagaki Takahiro wrote:
> I found the following warning with Fedora 14 / gcc 4.5.1.
> ----
> pg_backup_archiver.c: In function ‘_discoverArchiveFormat’:
> pg_backup_archiver.c:1736:11: warning: ‘fh’ may be used uninitialized
> in this function
> ----
> To suppress it, I'm thinking to add noreturn to die_horribly().
> Any objections? Another solution might be adding a dummy assignment
> after calls of die_horribly().

I added a dummy assignment, that's how we've handled this before in
pg_dump. I guess we could use noreturn, we already use it in pg_re_throw
function. But we also have a dummy exit(1) call in the PG_RE_THROW macro
for non-gcc compilers, so we might need to do that here too.

Thanks!

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com


From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc: Itagaki Takahiro <itagaki(dot)takahiro(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: add __attribute__((noreturn)) to suppress a waring
Date: 2011-01-24 15:14:42
Message-ID: 6210.1295882082@sss.pgh.pa.us
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Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
> On 24.01.2011 03:42, Itagaki Takahiro wrote:
>> To suppress it, I'm thinking to add noreturn to die_horribly().
>> Any objections? Another solution might be adding a dummy assignment
>> after calls of die_horribly().

> I added a dummy assignment, that's how we've handled this before in
> pg_dump.

We generally do *not* want to depend on noreturn, because it will not
suppress similar warnings in non-gcc compilers. Just add a dummy
initialization, or reorganize the code to avoid the problem.

regards, tom lane