Re: Overloaded operator question

Notice the operator<< functions here:

class failure : public ::std::exception {
   ::std::string whatStr;

public:
   explicit failure (char const* what_) : whatStr(what_)
   {}

   explicit failure (::std::string what_) : whatStr(::std::move(what_))
   {}

   ~failure () throw()
   {}

   char const* what () const throw()
   { return whatStr.c_str(); }

// failure& operator<< (char* s)
// {
// whatStr.append(s);
// return *this;
// }

   failure& operator<< (char const* s)
   {
     whatStr.append(s);
     return *this;
   }

   failure& operator<< (::std::string const& s)
   {
     whatStr.append(s);
     return *this;
   }

   template <class T>
   failure& operator<< (T val)
   {
     whatStr.append(::std::to_string(val));
     return *this;
   }
};

If I add back the commented out operator<< above the
following line is accepted by the compiler:

    if(argc!=2) throw failure("Usage: ")<<*argv<<" config-file-name";

But if it is stays commented out, I get an error:

/ErrorWords.hh: In instantiation of ?cmw::failure& cmw::failure::operator<<(T) [with T = char*]?:
cmwAmbassador.cc:309:44: required from here
./ErrorWords.hh:47:40: error: call of overloaded ?to_string(char*&)? is ambiguous
      whatStr.append(::std::to_string(val));

I'd like to be able to remove the commented out version
of that operator from the class. I guess the compiler
prefers the function template version to the version that
takes a char const*. Any ideas? Thanks.

Brian
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