Help for warning: type attributes are honored only at type definition

[Francesco Montorsi]

Maybe this is not the right list for such question?
Should I directly use gcc bugzilla?

Thanks,
Francesco


Francesco Montorsi ha scritto:
> Hi all,
>    I'm getting a lot of warnings of type:
> 
>     warning: type attributes are honored only at type definition
> 
> when building a library which uses the 
> __attribute__((visibility("default"))) also on forward declarations...
> 
> While I greatly appreciate the new C++ visibility support in GCC, I 
> think the above warning is a big malus for cross-platform projects which 
> need the M$'s __declspec() attribute also on forward declarations....
> 
> in fact reading
> 
>   http://gcc.gnu.org/wiki/Visibility
> 
> I see that this feature was designed with win32's declspec() 
> attribute-compatibility in mind. This has definitively been a Good Thing 
> but that warning does not make GCC fully compatible with __declspec.
> 
> To remove all those warnings from the sources of my apps I'd need to use 
> a DLLEXPORT_FORWARD macro when forward-declaring stuff (which would be 
> defined as __declspec(dllexport) for win32 compilers like MSVC or 
> Borland and which would expand to nothing for GCC).
> And that would require me to change thousands of lines by hand :(
> 
> Looking around for a solution (e.g. suppress that specific warning) I've 
> found:
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20345
> 
> and I wonder if the patch referenced there 
> (http://gcc.gnu.org/ml/gcc-patches/2006-06/msg01511.html) does fix my 
> problem, too. Does anyone know that?
> 
> In that case, which is the first GCC version which will include that patch?
> 
> Last, if that patch does not fix the warning, would it be possible to 
> add a -Wno-type-attribute-declaration (or something like that) switch to 
> suppress it?
> 
> 
> Thanks a lot and keep up the good work!
> Francesco Montorsi
> 
> 
> 
> PS: I'm using the following CC version:
> 
> frm@ubuntu:~$ gcc --version
> gcc (GCC) 4.1.2 20060928 (prerelease) (Ubuntu 4.1.1-13ubuntu5)
> 
> 
> 
>