New const char* ctor for C++-0x

[Jonathan Wakely]

2009/12/23 Jonathan Wakely:
> 2009/12/23 Ed Smith-Rowland:
>> +  const char * str01 = "010101000011";
>> +  std::bitset<n1> bit01(str01);
>
> Wouldn't this have passed anyway, without the new constructor?  I
> believe the point of the new constructor is to avoid the overhead of
> creating a std::string, but this test doesn't verify that.
> How about a type with a conversion to char* so that it would take too
> many conversions to go via the std::string constructor?

e.g.

#include <bitset>

struct X {
  operator const char* () { return "10101010"; }
};

int main()
{
  X x;
  std::string s(x);
  std::bitset<32> b1(x);
  std::bitset<32> b2(s);
  VERIFY( b1 == b2 );
}

With your patch applied this passes in c++0x mode, but not otherwise.