On Thursday 06 January 2005 16:38, John Maddock wrote:
The following section of code in utf8_codecvt_factet.hpp seems to be rather mixed up:
#if BOOST_WORKAROUND(__BORLANDC__,BOOST_TESTED_AT(0x551)) #ifndef _RWSTD_NO_NAMESPACE using std::codecvt; using std::min; #ifdef _RWSTD_NO_MBSTATE_T using std::mbstate_t; #endif #endif
This section imports codecvt, min and mbstate_t into the *global namespace*, why?
I don't know. This was a fix sent by an user (Pavel Vozenilek, I think) for some specific borland version. We failed to figure out why this works and what's the exact problem with that compiler.
Isn't this a "bad thing" in general?
I don't think so, in general. mbstate_t was in global namespace in C, after all.
I can't see why it would be necessary anyway.
#elif defined(__COMO__) || defined(_MSC_VER) && _MSC_VER <= 1300 typedef ::mbstate_t mbstate_t;
Surely this has no effect at best, or is illegal at worst? Remember we're in the global namespace here. Commenting this out has no effect on VC7 BTW (and VC6 doesn't build the lib anyway), can't comment on Commeau though.
#elif defined(BOOST_NO_STDC_NAMESPACE) typedef std::mbstate_t mbstate_t; namespace std{ using ::codecvt;
Again why import mbstate_t into the global namespace, especially as this does not happen for std conforming compilers?
Pavel, seems like the std::mbstate_t -> mbstate_t change was part of your patch (applied in revision 1.10 of utf_codecvt_facet.hpp). Do you remember why it was necessary?
Finally importing codecvt into namespace std:: is almost always likely to be an error: BOOST_NO_STDC_NAMESPACE refers to C library code, I don't know of any std lib that has codecvt, but doesn't put it in namespace std already.
In any case it doesn't build as is with gcc-2.95 (with or without STLport), but changing that to:
#elif defined(BOOST_NO_STDC_NAMESPACE) namespace std{ using ::mbstate_t; } // namespace std
and likewise changing the similar workaround convert.hpp to:
#if BOOST_WORKAROUND(__ICL, <= 700) || defined(BOOST_NO_STDC_NAMESPACE) #include <wchar.h> namespace std { using ::mbstate_t; } #endif
Gets it compiling with gcc-2.95 + STLport.
Hope this helps,
Yes, it does. Thank you! I'm just now trying to merge workarounds in program_options' and serialization's version of that file, so your suggestions are very welcome. - Volodya