Failure is the father of success.
esv::mbx is esvcpp meta boolean class type.
esv::mbx - esv::mb, the class type of esv::mb.
#include <esvcpp/core.hpp> int main() { constexpr esv::mbx x = true; constexpr esv::mbx y = false; esv::print(x, x.value(), y, y.value_ref()); // true true false false }