Juan Quintela wrote:
> * add VARRAY_UINT16_UNSAFE: unsafe here means that type checking is off
> (a.k.a. as a cast in C). In this case the problem is that the last
> element of one struct is int foo[0], and we allocate the right size
> for the array we want. Problem? I haven't been able to abuse^Wuse
> gcc + cpp + magic to typecheck that for vmstate:
>
> We have
> struct FOO {
> int32_t foo[0];
> }
> We want to "compare the type of foo (t1) with int32_t (t2)
>
> ((t1(*)[n])0 - (t2*)0)
> This one don't work, because we don't have 'n'
> ((t1(**))0 - (t2*)0)
> This don't work either because t1 is one array.
> ((t1(*)[])0 - (t2*)0)
> Too clever, imposible cast to on array type.
> I tried some other variants, but have not able to get one that compiles.
Since you mention GCC, is it ok to use GCC extensions? __typeof__(t1)
often does the trick for this sort of thing where t1 alone does not
compile, even if t1 is a type.
__builtin_types_compatible_p(), __builtin_choose_exper and
__attribute__((__error__)) are good for informative error messages.
-- Jamie
