Packing enums using the MSVC++ compiler

Question

With GCC, I could do packing of enums using attribute((packed)), but it seems the closest thing in MSVC, #pragma pack, does not work on enums. Does anyone know of a way to pack enums into 1 byte instead of the usual integer size?

Answer 1

This is MSVC specific:

// instances of this enum are packed into 1 unsigned char
// warning C4480: nonstandard extension used
enum foo : unsigned char { first, second, last }; 
assert(sizeof(foo) == sizeof(unsigned char));

// instances of this enum have the common size of 1 int
enum bar { alpha, beta, gamma };
assert(sizeof(bar) == sizeof(int));

For reference see here: MSDN -> enum