The built-in comma operator has strict sequencing semantics: Every value computation and side effect of the first (left) argument of the built-in comma operato

The built-in comma operator has strict sequencing semantics: Every value computation and side effect of the first (left) argument of the built-in comma operator , is sequenced before every value computation and side effect of the second (right) argument. [1] The same sequencing guarantee is not applied to a user-defined comma operator. For the similar reasons it's not a great idea to overload && and || either. [1] https://en.cppreference.com/w/cpp/language/eval_order https://en.cppreference.com/w/cpp/language/eval_order (point 9)