auto for class members

Question

Here is a piece of code:

class foo
{
   auto data;
   const auto MAX;
   auto msg;

public:
   foo(int val, string m) :
      data(val),
      msg(m),
      MAX("42")
   {}
};

The compiler shows 2 errors:

cpp_auto.cpp(23) : error C2440: 'initializing' : cannot convert from 'std::string' to 'auto'
        No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
cpp_auto.cpp(23) : error C2439: 'foo::msg' : member could not be initialized
        c:\users\administrator\documents\visual studio 10\projects\cpp_auto\cpp_auto.cpp(16) : see declaration of 'foo::msg'

It looks like it treats auto as int (default type when none specified?), but then why does initializing the MAX constant with a string works. As far as I know, auto can only be used locally. So I think there are some problems here with the compiler.

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Microsoft MVP VC++ | www.mariusbancila.ro | www.mariusbancila.ro/blog

Answer 1

Hi Marius: this is a bug - the code should not compile but the error message is not the best. We'll fix this for the next release.

Jonathan Caves 

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Jonathan Caves - Visual C++ Compiler Team