On 02/04/10 12:17, Christoph Bartoschek wrote:
> Hi,
>
> what is the recommended way to call __sync_val_compare_and_swap for a float
> pointer?
Does it not work with a float pointer?
> On the platforms where the code should run a float is 4 bytes. Therefore we
> casted to an int pointer which is also 4 bytes. However this gives us a
> warning:
>
> warning: dereferencing type-punned pointer will break strict-aliasing rules
>
> How to do this correctly?
Use a union:
typedef union
{
int i; float f;
] u_t;
u_t *up;
u_t u, u1;
u.f = floatval;
u1.f = oldval;
__sync_val_compare_and_swap (&up->i, u1.i, u.i);
Andrew.
