I'm looking for a way, to *statically* know if my type's ".init" value is nothing but zeros.

I need this to initialize a dynamic array: If the T.init is nothing but 0, then I can just memset the whole array in a single call. Otherwise, I have to memcpy T.init individually N times.

Currently, I can (runtime) use "typeid(T).init.ptr": Types that don't have an an elaborate .init will return null.

I'm trying to find the same result, without a runtime check. Anybody know how? I'd write a function that tests the bits of a T.init copy, but reinterpreting is not allowed during CTFE...

On Monday, 5 May 2014 at 20:54:52 UTC, monarch_dodra wrote:
> I'm looking for a way, to *statically* know if my type's ".init" value is nothing but zeros.
>
> I need this to initialize a dynamic array: If the T.init is nothing but 0, then I can just memset the whole array in a single call. Otherwise, I have to memcpy T.init individually N times.
>
> Currently, I can (runtime) use "typeid(T).init.ptr": Types that don't have an an elaborate .init will return null.
>
> I'm trying to find the same result, without a runtime check. Anybody know how? I'd write a function that tests the bits of a T.init copy, but reinterpreting is not allowed during CTFE...

Foreach member x of Type X of T, check if T.init.x equals X.init?

On Monday, 5 May 2014 at 21:51:14 UTC, Tobias Pankrath wrote
>> I'm trying to find the same result, without a runtime check. Anybody know how? I'd write a function that tests the bits of a T.init copy, but reinterpreting is not allowed during CTFE...
>
> Foreach member x of Type X of T, check if T.init.x equals X.init?

Ah, sorry, didn't read carefully. This is not what you want.

On Monday, 5 May 2014 at 21:54:33 UTC, Tobias Pankrath wrote:
> On Monday, 5 May 2014 at 21:51:14 UTC, Tobias Pankrath wrote
>>> I'm trying to find the same result, without a runtime check. Anybody know how? I'd write a function that tests the bits of a T.init copy, but reinterpreting is not allowed during CTFE...
>>
>> Foreach member x of Type X of T, check if T.init.x equals X.init?
>
> Ah, sorry, didn't read carefully. This is not what you want.

Actually, I think you're on to something. I can recursively iterate on all basic types in my T, and check they are all "0" or NULL. Should work.

Thanks!