Problem with ostringstream and copy constructor [duplicate]

Answer 1

std::ostringstream is not copyable that's why you are getting error. See this answer for more details to know how you can overcome this problem.

T(const T& t)  {log << t.log.rdbuf(); }

Answer 2

Copy constructor and copy-assignment of any stream class in C++ has been made private. That means, you cannot make copy of std::ostringstream object:

std::ostringstream ss;

std::ostringstream ss1(ss); //not allowed - copy-constructor is private
ss1=ss; //not allowed - copy-assignment is private

Answer 3

I think ostringstream has no overloaded assignment(=) operator.