Frederic Bouvier schrieb:
> Hi Stefan,
>
> ----- "Stefan C. Müller" a écrit :
>
>> Small patch fixing bugs I've encountered while getting the current CVS
>> to build in MSVC.
>> * std::lower_bound was used with the key-type of a map, but
>> lower_bound expects the value-type of the collection it works on, with is
>> std::pair. MSVC seems to be more strict about this.
>>
>
> As far as I can tell, this is not true. The third parameter type is
> independant from the type of the container, and should only match the type of
> the second parameter of the predicate. The current code compile under MSVC
> 7.1 and under MSVC 9.0. Looking at the lower_bound code in the MSVC 8
> <algorithm>, I think it is the same for VS2005.
> What is your msvc version, and what is the error message you are seeing ?
>
> -Fred
I'm using VC Express 2005 (SP1). I must say I was rather confused to see
that this does not work in MSVC. I tracked it down into xutility and
found that the error was actually caused by debugging code that will
later be thrown away be the optimizer anyway. Heres the part:
template<class _Pr, class _Ty1, class _Ty2> inline
bool __CLRCALL_OR_CDECL _Debug_lt_pred(_Pr _Pred, _Ty1& _Left, const
_Ty2& _Right,
const wchar_t *_Where, unsigned int _Line)
{ // test if _Pred(_Left, _Right) and _Pred is strict weak ordering
if (!_Pred(_Left, _Right))
return (false);
else if (_Pred(_Right, _Left)) // THIS IS LINE 314 (see
error message)
_DEBUG_ERROR2("invalid operator<", _Where, _Line);
return (true);
}
It checks if the predicate (orderingFunctor) is commutative. The
_DEBUG_ERROR2 macro seems to lead into an emtpy function, so it has no
effect at the end but caused the build to fail. The _Left is the result
of dereferencing an iterator (with leads to std::pair) and _Right is the
string given to lower_bound. Who ever wrote this code had a vector or a
list in mind and not a map.
I see two ways to work around this, the one I've chosen most certainly
fixes the problem on all possible implementations of std::lower_bound.
The other is to overload the operator() in the functor for all tree
parameter combinations operator()(std::pair, std::string),
operator()(std::string, std::pair) and operator()(std::pair,std::pair)
(the pair,pair is required because of another debugging check in VC's
implementation). But this is even more ugly and might still break on
other c++ suites.
Maybe you find a better way to do this. Having a dirty hack as my first
contribution is not exactly what I hoped for :-)
Heres the complete error message (for the one in fixlist.cpp) The
messages are in german, sorry for that, I don't know how to get rid of
the localization.
fixlist.cxx
1>c:\programme\microsoft visual studio 8\vc\include\xutility(314) :
error C2664: 'bool orderingFunctor::operator ()(const
std::pair<_Ty1,_Ty2> &,const std::string &) const': Konvertierung des
Parameters 1 von 'const std::string' in 'const std::pair<_Ty1,_Ty2> &'
nicht möglich
1> with
1> [
1> _Ty1=const std::string,
1> _Ty2=FGFix
1> ]
1> Ursache: Konvertierung von 'const std::string' in 'const
std::pair<_Ty1,_Ty2>' nicht möglich
1> with
1> [
1> _Ty1=const std::string,
1> _Ty2=FGFix
1> ]
1> Kein benutzerdefinierter Konvertierungsoperator verfügbar, der
diese Konvertierung durchführen kann, oder der Operator kann nicht
aufgerufen werden
1> c:\programme\microsoft visual studio
8\vc\include\algorithm(2304): Siehe Verweis auf die Instanziierung der
gerade kompilierten Funktions-template "bool
std::_Debug_lt_pred<_Pr,std::pair<_Ty1,_Ty2>,_Ty>(_Pr,std::pair<_Ty1,_Ty2>
&,const std::basic_string<_Elem,_Traits,_Ax> &,const wchar_t *,unsigned
int)".
1> with
1> [
1> _Pr=orderingFunctor,
1> _Ty1=const std::string,
1> _Ty2=FGFix,
1> _Ty=std::string,
1> _Elem=char,
1> _Traits=std::char_traits<char>,
1> _Ax=std::allocator<char>
1> ]
1> c:\programme\microsoft visual studio
8\vc\include\algorithm(2318): Siehe Verweis auf die Instanziierung der
gerade kompilierten Funktions-template "_FwdIt
std::_Lower_bound<std::_Tree<_Traits>::iterator,_Ty,__w64
int,_Pr>(_FwdIt,_FwdIt,const _Ty &,_Pr,_Diff *)".
1> with
1> [
1>
_FwdIt=std::_Tree<std::_Tmap_traits<std::string,FGFix,std::less<std::string>,std::allocator<std::pair<const
std::string,FGFix>>,true>>::iterator,
1>
_Traits=std::_Tmap_traits<std::string,FGFix,std::less<std::string>,std::allocator<std::pair<const
std::string,FGFix>>,true>,
1> _Ty=std::string,
1> _Pr=orderingFunctor,
1> _Diff=__w64 int
1> ]
1>
d:\projects\flightgear\buildenv\flightgear\src\navaids\fixlist.cxx(158):
Siehe Verweis auf die Instanziierung der gerade kompilierten
Funktions-template "_FwdIt
std::lower_bound<std::_Tree<_Traits>::iterator,std::string,orderingFunctor>(_FwdIt,_FwdIt,const
_Ty &,_Pr)".
1> with
1> [
1>
_FwdIt=std::_Tree<std::_Tmap_traits<std::string,FGFix,std::less<std::string>,std::allocator<std::pair<const
std::string,FGFix>>,true>>::iterator,
1>
_Traits=std::_Tmap_traits<std::string,FGFix,std::less<std::string>,std::allocator<std::pair<const
std::string,FGFix>>,true>,
1> _Ty=std::string,
1> _Pr=orderingFunctor
1> ]
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