cast odd boundary?

[Devrobcom]

Hi

I have read somwhere that this problem is handled by the
Intel cpu's (firmware), but what will happen on other types of cpu's.

struct
{
char aa; // even boundary 0xaa00
char bb[4]; // assume on odd boundary 0xaa01
} mstr;

long ll;
ll = *((long*)mstr.bb); // no: 1 do i get an exception?

*((long*)mstr.bb) = ll; // no: 2 do i get an exception?

/dev

 

[Clark Cox]

Hi

I have read somwhere that this problem is handled by the
Intel cpu's (firmware), but what will happen on other types of cpu's.

struct
{
char aa; // even boundary 0xaa00
char bb[4]; // assume on odd boundary 0xaa01
} mstr;

Assuming that that is the case (i.e. there is no padding between aa
and bb, and sizeof(long) == 4).

long ll;
ll = *((long*)mstr.bb); // no: 1 do i get an exception?

You could get an exception, or you app could simply crash, or monkeys
could spring forth from your gut , as that is undefined behavior. Many
platforms require special alignment for particular types.

*((long*)mstr.bb) = ll; // no: 2 do i get an exception?

Same answer