Compile error with gcc

[Julio Merino]

On Feb 16, 2014, at 8:05, Dimitry Andric <dim at FreeBSD.org> wrote:

> On 16 Feb 2014, at 13:45, Julio Merino <jmmv at outlook.com> wrote:
>> On Feb 16, 2014, at 7:11, Dimitry Andric <dim at FreeBSD.org> wrote:
>>> 
>>> I don't think this will always work correctly.  If MK_LIBCPLUSPLUS is
>>> defined in bsd.own.mk, it only means libc++ is being *built*, not that
>>> it is being used.
>>> 
>>> It is probably easier and more fool-proof to check if _LIBCPP_VERSION is
>>> defined (which is the case when you use libc++) in bconfig.h, like so:
>>> 
>>> Index: contrib/atf/bconfig.h
>>> ===================================================================
>>> --- contrib/atf/bconfig.h       (revision 261974)
>>> +++ contrib/atf/bconfig.h       (working copy)
>>> @@ -56,7 +56,9 @@
>>> #define HAVE_UNSETENV 1
>>> 
>>> /* Define to 1 if vsnprintf is in std */
>>> +#ifdef _LIBCPP_VERSION
>>> #define HAVE_VSNPRINTF_IN_STD 1
>>> +#endif
>> 
>> Let's not do that unless we can change configure.ac to generate these same contents.
>> 
>> Maybe we can just revert this to _not_ define HAVE_VSNPRINTF_IN_STD as it used to be the case before the new import?  Things were working just fine with both libstdc++ and libc++ even if that setting was not accurate for the latter...
> 
> Well, contrib/atf/atf-c++/detail/application.cpp has:
> 
> #if !defined(HAVE_VSNPRINTF_IN_STD)
> namespace std {
> using ::vsnprintf;
> }
> #endif // !defined(HAVE_VSNPRINTF_IN_STD)
> 
> so it sort of hacks around it anyway. :-)

Right, so what does C++ say about this?  Is that snippet OK even when std::vsnprintf is already defined, as is the case for libc++?  (I.e. won't that using directive ever conflict with the library?)

If the above is true, then I'd just kill the whole HAVE_VSNPRINTF_IN_STD stupidity from both bconfig.h and application.cpp!