how to use std::rel_ops to supply comparison operators automatically? [duplicate]

Answer 1

I'd use the header :

#include 

struct S : private boost::totally_ordered
{
  bool operator<(const S&) const { return false; }
  bool operator==(const S&) const { return true; }
};

int main () {
  S s;
  s < s;
  s > s;
  s <= s;
  s >= s;
  s == s;
  s != s;
}

---

Or, if you prefer non-member operators:

#include 

struct S : private boost::totally_ordered
{
};

bool operator<(const S&, const S&) { return false; }
bool operator==(const S&, const S&) { return true; }

int main () {
  S s;
  s < s;
  s > s;
  s <= s;
  s >= s;
  s == s;
  s != s;
}