Wireshark · Wireshark-dev: Re: [Wireshark-dev] "Type-punned pointer... breaks anti-aliasing rules" in dfilter-macro.c

[Gilbert Ramirez <gram@xxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxx> 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@xxxxxxxxx> 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@xxxxxxxxxxx> 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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