Re: [Libreoffice-commits] core.git: Silence some conversion warnings

[putting the ML back into the loop]

On 08/24/2015 10:56 AM, Matteo Casalin wrote:
> On Mon, 24 Aug 2015 10:37:38 +0200
> Stephan Bergmann <sbergman@redhat.com> wrote:
>
> > On 08/21/2015 10:30 PM, Matteo Casalin wrote:
> > > commit eb4cbea657b9038c488f1b1bcf5107cc226a6681
> > > Author: Matteo Casalin <matteo.casalin@yahoo.com>
> > > Date:   Sun Aug 16 16:32:13 2015 +0200
> > >
> > >       Silence some conversion warnings
> > >
> > >       Change-Id: I676ed010576f3a24b193ffc6c28a319bcc5ac968
> > [...]
> > > diff --git a/store/source/storbase.hxx b/store/source/storbase.hxx
> > > index 395870f..78a51a1 100644
> > > --- a/store/source/storbase.hxx
> > > +++ b/store/source/storbase.hxx
> > > @@ -512,9 +512,9 @@ struct PageData
> > >        void guard (sal_uInt32 nAddr)
> > >        {
> > >            sal_uInt32 nCRC32 = 0;
> > > -        nCRC32 = rtl_crc32 (nCRC32, &m_aGuard.m_nMagic, sizeof(sal_uInt32));
> > > +        nCRC32 = rtl_crc32 (nCRC32, &m_aGuard.m_nMagic, 
> > > static_cast<sal_uInt32>(sizeof(sal_uInt32)));
> >
> > What compiler/switch is it that warns there?  It does not look like that
> > particular compiler/switch is very useful.  sizeof(sal_uInt32) is a
> > known, small integer at compile time.  It should be apparent to both the
> > compiler and humans that it fits into the sal_uInt32 argument to
> > rtl_crc32 without needing the static_cast noise.
>
> That's GCC -Wconversion, which I'm using to chase harmful downcasts (e.g. sal_Int32 to sal_uInt16 
> for OUString length, there are still some of them here and there). The point is that some of these 
> downcasts, although safe in themselves, introduce a lot of noise in the logs and make the real 
> issues difficult to detect.
> If I remember correctly in this case the warning was probably only in the result of "theSize - sizeof(G)" 
> some lines below, I just casted both call places for simmetry. If that's undesired I'll revert the cast for the 
> "sizeof(sal_uInt32)" calls.

So you're actually finding problems with that?  Good to know---probably 
makes the resulting increase in noise more tolerable. ;)

Anyway, if any of those "obvious" casts are not actually needed by your 
toolchain to silence warnings, then yes, might be good if you just 
removed those again.