Method equivalent

system/lib/libcxx/src/error_category.cpp:29–31

error_condition error_category::default_error_condition(int ev) const noexcept { return error_condition(ev, *this); }

bool error_category::equivalent(int code, const error_condition& condition) const noexcept {
  return default_error_condition(code) == condition;
}

bool error_category::equivalent(const error_code& code, int condition) const noexcept {
  return *this == code.category() && code.value() == condition;