Bug#925771: lmms: ftbfs with GCC-9

[Philip Chung <philipchung1995@yahoo.com>]

On Wed, 27 Mar 2019 19:46:58 +0000 Matthias Klose <doko@debian.org> wrote:
> Package: src:lmms
> Version: 1.1.3-8.1
> Severity: normal
> Tags: sid bullseye
> User: debian-gcc@lists.debian.org
> Usertags: ftbfs-gcc-9
> 
> [...]
>
> The package fails to build in a test rebuild on at least amd64 with
> gcc-9/g++-9, but succeeds to build with gcc-8/g++-8. The
> severity of this report will be raised before the bullseye release,
> so nothing has to be done for the buster release.
> 
> The full build log can be found at:
> http://people.debian.org/~doko/logs/gcc9-20190321/lmms_1.1.3-8.1_unstable_gcc9.log
> The last lines of the build log are at the end of this report.
> 
> [...]
>
> /<<PKGBUILDDIR>>/plugins/LadspaEffect/calf/src/calf/giface.h: In instantiation of 'calf_plugins::audio_module<Metadata>::audio_module() [with Metadata = calf_plugins::monosynth_metadata]':
> /<<PKGBUILDDIR>>/plugins/LadspaEffect/calf/src/monosynth.cpp:34:22:   required from here
> /<<PKGBUILDDIR>>/plugins/LadspaEffect/calf/src/calf/giface.h:458:15: error: 'memset' used with length equal to number of elements without multiplication by element size [-Werror=memset-elt-size]
>   458 |         memset(ins, 0, sizeof(ins));
>       |         ~~~~~~^~~~~~~~~~~~~~~~~~~~~
> cc1plus: all warnings being treated as error>
> [...]

It seems the warning (turned error) is being raised in this case because
the in_count is 0, so the element size and the array size are the same.

Regardless of this warning, it seems the code is correct: It sets the
bytes of the entire array to zero. Of course, it could be changed to the
classic (elements) * (element size) to remove this warning, but I wonder
if there is another way to suppress it.

Philip Chung