GNU bug report logs - #20536
avoid new gcc warning: ENOTSUP vs EOPNOTSUPP

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: bug-coreutils <at> gnu.org
Subject: avoid new gcc warning: ENOTSUP vs EOPNOTSUPP
Date: Sat, 9 May 2015 11:15:07 -0700

[Message part 1 (text/plain, inline)]

Building with very new gcc-from-git, I encountered 3 new warnings.
Here's a patch to address them:

Without this change, very recent gcc (e.g., version 6.0.0 20150509)
would print the following when configured with --enable-gcc-warnings:

  src/copy.c:165:30: error: logical 'or' of equal expressions \
    [-Werror=logical-op]
    && (errno == EOPNOTSUPP || errno == ENOTSUP || errno == ENOSYS))
                           ^
* src/system.h (is_ENOTSUP): New function.
* src/copy.c (punch_hole): Use it.
* src/ls.c (errno_unsupported, gobble_file): Use it.

[0001-build-avoid-a-warning-form-gcc-s-new-Wlogical-op.patch (application/octet-stream, attachment)]

Message #10 received at 20536-done <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Jim Meyering <jim <at> meyering.net>, 20536-done <at> debbugs.gnu.org
Subject: Re: bug#20536: avoid new gcc warning: ENOTSUP vs EOPNOTSUPP
Date: Sat, 09 May 2015 23:19:41 +0100

On 09/05/15 19:15, Jim Meyering wrote:
> Building with very new gcc-from-git, I encountered 3 new warnings.
> Here's a patch to address them:
> 
> Without this change, very recent gcc (e.g., version 6.0.0 20150509)
> would print the following when configured with --enable-gcc-warnings:
> 
>   src/copy.c:165:30: error: logical 'or' of equal expressions \
>     [-Werror=logical-op]
>     && (errno == EOPNOTSUPP || errno == ENOTSUP || errno == ENOSYS))
>                            ^
> * src/system.h (is_ENOTSUP): New function.
> * src/copy.c (punch_hole): Use it.
> * src/ls.c (errno_unsupported, gobble_file): Use it.

Not sure I agree with GCC's warning here,
but the fix looks good.

Marking this as done.

thanks!
Pádraig

Message #13 received at 20536 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Jim Meyering <jim <at> meyering.net>, 20536 <at> debbugs.gnu.org
Subject: Re: bug#20536: avoid new gcc warning: ENOTSUP vs EOPNOTSUPP
Date: Sun, 10 May 2015 07:17:15 -0700

Jim Meyering wrote:
> +  return err == EOPNOTSUPP
> +#if ENOTSUP != EOPNOTSUPP
> +    || err == ENOTSUP
> +#endif
> +    ;

Would the following work instead?  It's a bit cleaner to avoid #if:

  return err == EOPNOTSUPP || (ENOTSUP != EOPNOTSUPP && err == ENOTSUP);

Message #16 received at 20536 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 20536 <at> debbugs.gnu.org
Subject: Re: bug#20536: avoid new gcc warning: ENOTSUP vs EOPNOTSUPP
Date: Sun, 10 May 2015 08:34:51 -0700

On Sun, May 10, 2015 at 7:17 AM, Paul Eggert <eggert <at> cs.ucla.edu> wrote:
> Jim Meyering wrote:
>>
>> +  return err == EOPNOTSUPP
>> +#if ENOTSUP != EOPNOTSUPP
>> +    || err == ENOTSUP
>> +#endif
>> +    ;
>
> Would the following work instead?  It's a bit cleaner to avoid #if:
>
>   return err == EOPNOTSUPP || (ENOTSUP != EOPNOTSUPP && err == ENOTSUP);

I confirmed that too avoids the warning, so I've pushed it in your name.

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