Is char signed or unsigned on OS X C++

Question

Is char signed or unsigned on OS X.

I put the following snippet together to test, but was wondering how to tell for sure?

char a(0x80);           //fill most sig bit 
unsigned char b(0x80);  //fill most sig bit

cout<<"char ";
(a==b)? cout<<"is not" : cout<<"is";    //compare most sig bits in diff't chars
cout<<" signed\n";

The result was: char is signed

I'd like to know how to find this out without a piece of trick code.

Answer 1

Check the value of std::numeric_limits<char>::is_signed

#include <iostream>
#include <limits>

int main() {
  std::cout << "char "
            << (std::numeric_limits<char>::is_signed ? "is" : "is not")
            << " signed.\n";
  return 0;
}