switch (long long) standard?


While developing a state machine compiler I came to a point where I would like the state machine to do a switch() based on current state + event, both being enums.

Would it be portable and standards compliant to do something similar to

enum states { ...... } current_state;
enum events { ...... } received_event;

#define INT_BITS (CHAR_BIT * sizeof (int))
#define mix(a,b) (((unsigned long long) (a)) << INT_BITS | (b))
    switch (mix(current_state, received_event)) {

       case mix(foo, bar) :


I don't have access to the standards so I can't check my assumptions but I understand that an enum is actually an int and that I need, at minimum, a long long to hold the value of two ints side by side. Is this correct?

And, what I really don't know, is if switch () can work on any size integral type or only on int

Thanks for any help

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