Re: "Type-punned pointer... breaks anti-aliasing rules" in dfilter-macro.c

[Gilbert Ramirez <gram () alumni rice edu>]

I have attempted a code fix to remove all the -fstrict-alias warnings
uncovered by the old version of gcc I am using.

https://code.wireshark.org/review/#/c/40/

Gilbert


On Wed, Jan 29, 2014 at 4:37 AM, Gilbert Ramirez <gram () alumni rice edu>wrote:

> I'm encountering the same problem building on an old RedHat 5.0 system,
> using gcc 4.1.2.  Was there any fix committed to add -fno-strict-aliasing
> for some configurations? (there doesn't appear to be)
>
> Gilbert
>
>
> On Tue, Jun 18, 2013 at 6:09 PM, Evan Huus <eapache () gmail com> wrote:
>
> > Probably the simplest fix is to add -fno-strict-aliasing to the build
> > flags on FreeBSD.
> >
> > On 2013-06-18, at 4:14 PM, Stephen Fisher <
> > stephenfisher-wireshark () outlook com> wrote:
> >
> > > When trying to compile Wireshark (SVN trunk) on FreeBSD for the first
> > time in a long time, I ran across a familiar error:
> > >     dfilter-macro.c: In function 'dfilter_macro_init':
> > >     dfilter-macro.c:614: warning: dereferencing type-punned pointer
> > will break strict-aliasing rules
> > > However, line 614 has a history of being changed between this:
> > >
> > >     (void*) &macros,
> > >
> > > and this (as it currently is):
> > >
> > >     (void**) &macros,
> > >
> > > Which is the fifth parameter in a call to uat_new() where parameter
> > five's type is "void** data_ptr" and macros is type dfilter_macro_t*.
> > > This was most recently changed with SVN revision 48355 that Anders
> > committed in response to bug 8416 ("remove C++ incompatibilities")
> > according to the SVN log.  Before that, judging by the "svn annotate"
> > output in Emacs of a few lines earlier, I changed it from (void**) to
> > (void*) way back in 2007 as SVN revision 21330 to "Fix warnings on
> > Linux/gcc 4.1.1" and it may have changed at other times as well.
> > > What should the fix ultimately be if one way breaks FreeBSD/gcc 4.2.1
> > compiles and if it introduces C++ compatibility issues (which I'm not
> > familiar with since I haven't been following development for a while
> > lately).
> > >
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