Bug 582792 – media-libs/audiofile-0.3.6-r1: building w/gcc-6: error: left operand of shift expression '(-1 << 7)' is negative [-fpermissive]

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Peter Levine 2016-05-12 02:28:58 UTC]

Left bitwise-shifting of a negative integer type is now nonconformant with gcc-6.

I made an upstream pull request pending approval:

https://github.com/mpruett/audiofile/pull/28

[Comment 1 Roman Beránek 2016-05-22 15:02:44 UTC]

Created attachment 434972 [details, diff]
Add -fpermissive to CXXFLAGS to avoid errors with gcc-v6

[Comment 2 Roman Beránek 2016-05-22 15:04:01 UTC]

What about adding the '-fpermissive' flag as the gcc itself suggest?

[Comment 3 Roman Beránek 2016-05-22 15:05:38 UTC]

Comment on attachment 434972 [details, diff]
Add -fpermissive to CXXFLAGS to avoid errors with gcc-v6

What about adding the '-fpermissive' flag as the gcc itself suggest?

[Comment 4 Roman Beránek 2016-05-22 15:07:35 UTC]

(I'm sorry for the mess, this is my first time using bugzilla, didn't know you can't edit nor delete a comment.)

[Comment 5 Peter Levine 2016-05-23 16:07:00 UTC]

C++14 dialect forces the programmer to explicitly declare his/her intent to code something potentially dangerous that might have been assumed to be fine in C++98 dialect.  You can add -fpermissive and/or -std=c++98 flag to overcome most gcc-6 related errors but it's really a bandaid over the problem.  Though some upstream developers have chosen this route, IMHO it should be avoided if possible and a dialect neutral solution should be preferred.

[Comment 6 Francesco Turco 2016-08-31 13:39:12 UTC]

I confirm adding -fpermissive to CXXFLAGS "fixes" the problem.

[Comment 7 Jonathan Scruggs (RETIRED) 2016-10-27 16:41:36 UTC]

Created attachment 451648 [details, diff]
audiofile-0.3.6-gcc6-build-fixes.patch

Adding the compiler flag does not fix the underlying issues.

Please find attached the proper patch that fixes the issues. It's compatible with all versions of GCC officially in portage now. :)

To use this:
Save the attached patch with the description name.
Place it in /etc/portage/patches/media-libs/audiofile/
The ebuild does not need to be modified as it will pick up this patch and apply it.

Cheers.

[Comment 8 David Seifert 2016-10-28 22:38:40 UTC]

commit db5ba8d0625e670e679f558e0943006f238f952b
Author: Jonathan Scruggs <[e-mail]>
Date:   Fri Oct 28 10:31:09 2016 +0100

    media-libs/audiofile: Add gcc 6 build fixes patch
    
    Gentoo-bug: 582792
    
    Signed-off by: Jonathan Scruggs ([e-mail])
    Closes: https://github.com/gentoo/gentoo/pull/2684
    
    Signed-off-by: David Seifert <[e-mail]>