Re: [boost] alignment trouble with boost::optional

Fernando Cacciola wrote:

struct Echar { E e ; char c; } ;

struct charE { char c; E e ; } ;

sizeof(Echar) -> 24 sizeof(charE) -> 32

As you can see, the true alignment of T is 4, while 12 is just 3 times that.

The "preferred" alignment of E seems to be 8 (makes sense because of the long long), which is why the sizes are a multiple of 8. Why is sizeof(E) 20, however, I don't know. Alignments are tricky.