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Re: [Patch 4.6] In system.h, wrap include of C++ header in 'extern C++'
On Fri, Jun 15, 2012 at 11:59 AM, Duncan Sands <baldrick@free.fr> wrote:
> Hi Richard,
>
>
>> Uh, I don't think we should do that. ?Why do we include cstring here
>> anyways?
>>
>> Ian - you added this include in rev. 167764, I don't think that was
>> "proper".
>> But I'm not sure wrapping a system.h include inside extern "C" from a C++
>> plugin is proper either ...
>
>
> since the plugin needs to call GCC routines, and GCC is built as C, it has
> to
> wrap at least some GCC headers in "extern C" to avoid mangling of the names
> of those GCC routines (otherwise you can't load the plugin because the
> linker
> will look for the mangled names in GCC and not find them). ?But perhaps you
> know a trick to avoid the name mangling problem? ?It is true that maybe via
> a careful dance it is possible to not wrap system.h in "extern C" - I will
> give it a go.
As system.h is supposed to only include system headers and do nothing
else it has to be prepared to be included from C++ already, so no extern "C"
wrapping should be necessary for it.
Richard.
> Ciao, Duncan.
>
>
>>
>> Thanks,
>> Richard.
>>
>>> Thanks, Duncan.
>>>
>>> Index: gcc/system.h
>>> ===================================================================
>>> --- gcc/system.h ? ? ? ?(revision 188518)
>>> +++ gcc/system.h ? ? ? ?(working copy)
>>> @@ -191,7 +191,9 @@
>>> ?#endif
>>>
>>> ?#ifdef __cplusplus
>>> +extern "C++" {
>>> ?# include<cstring>
>>> +}
>>> ?#endif
>>>
>>> ?/* Some of glibc's string inlines cause warnings. ?Plus we'd rather
>
>