taglib fails to compile with MS VC++ 2010

[Tanguy Krotoff]

** Summary: yes this patch is perfect! it makes the code compliant
with the new version C++0x (still to be released)

** More details:

The error simplified is:
mpegheader.cpp(172) : error C2668: 'std::bitset<_Bits>::bitset' :
ambiguous call to overloaded function
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\bitset(136):
could be 'std::bitset<_Bits>::bitset(_ULonglong)'
C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\bitset(127):
or 'std::bitset<_Bits>::bitset(int)'
while trying to match the argument list '(TagLib::uint)'

This is Visual C++ 2008 bitset constructor:
http://msdn.microsoft.com/en-us/library/zfae7kt8(v=VS.90).aspx
bitset(
   unsigned long _Val
);[...]

This is Visual C++ 2010 bitset constructor:
http://msdn.microsoft.com/en-us/library/zfae7kt8(v=VS.100).aspx
bitset(
   unsigned long long _Val
);

This is a change due to the new C++ version C++0x (still to be
released...) cf bitset source code from Visual C++ 2010 on my hard
drive (see http://www.codeguru.com/cpp/article.php/c18259 for more
explanations about _HAS_CPP0X):

[...]
 #if _HAS_CPP0X
	bitset(int _Ival)        <-------- line 127
		{	// construct from bits in int
		unsigned int _Val = (unsigned int)_Ival;
		_Tidy();
		for (size_t _Pos = 0; _Val != 0 && _Pos < _Bits; _Val >>= 1, ++_Pos)
			if (_Val & 1)
				set(_Pos);
		}

	bitset(_ULonglong _Val)       <-------- line 136

 #else /* _HAS_CPP0X */
	bitset(unsigned long _Val)
 #endif /* _HAS_CPP0X */
[...]

More explanations about this change in C++0x :
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2795.html#694
"[...]replace the bitset ctor that takes an unsigned long argument
with one taking unsigned long long in the definition of the template"



2011/1/16 Lukáš Lalinský <lalinsky at gmail.com>:
> On Fri, Jan 14, 2011 at 11:05 AM, Tanguy Krotoff <tkrotoff at gmail.com> wrote:
>> Hi everybody.
>>
>> Any chance to get this patch on trunk?
>
> I'll commit it, but can somebody please explain to me why is it
> necessary to cast the value to "unsigned long long". From what I can
> see, the std::bitset class has only "unsigned long" constructor.
> Shouldn't it be casted to "unsigned long" instead?
>
> Lukas
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