How can I check if a class has operator<< defined for it?

Asked Jan 31 '19 at 16:20

Active Jan 31 '19 at 16:31

Viewed 44 times

How can I check if std::cout << myClass; is valid? I'd like to do something like:

class Logger {
 public:
  // Some kind of enable_if(operator<< doesn't exist)
  void printMyClass(MyClass& my_class) {
    std::cout << "Got a myclass" << std::endl;
  }   

  // Some kind of enable_if(operator<< exists)
  void printMyClass(MyClass& my_class) {
    std::cout << "Got a myclass: " << my_class << std::endl;
  }   

};

edited Jan 31 '19 at 16:31

balki

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asked Jan 31 '19 at 16:20

Thomas Johnson

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Possible duplicate : https://stackoverflow.com/questions/12980508/best-way-to-check-for-existence-of-an-operator-in-c11 – François Andrieux Jan 31 '19 at 16:24
Not a dupe, because operator<< doesn't have to be a member function – Thomas Johnson Jan 31 '19 at 16:24
Instantiate and step through it with visual studio debugger – Callat Jan 31 '19 at 16:24
@Callat I'm pretty sure OP want's to know at compile time and have the compiler resolve which function to call based on that knowledge. – François Andrieux Jan 31 '19 at 16:25
1

Thanks, you're right the second is what I was looking for. I voted to self-close as dupe – Thomas Johnson Jan 31 '19 at 16:26

How can I check if a class has operator<< defined for it?

0 Answers0