Hi Stefan,

A Builder already acts like a pointer: You can copy it by value, and the
copy manipulates the same underlying message.

If you just want to express the type "capnp::Builder or null", then I
suggest using `kj::Maybe<capnp::Builder>`, which serves exactly this
purpose. A `kj::Maybe<T>` can be assigned to any `T` or to `nullptr`. You
can unpack a Maybe with `KJ_IF_MAYBE()`. Check out the comments in
`kj/commen.h` and copious examples throughout the KJ and Cap'n Proto source
code to learn more.

-Kenton

On Wed, Sep 4, 2019 at 11:10 AM Stefan Kaps <[email protected]> wrote:

> Hi,
>
> i would like to use pointers to builders in my exporter, so I can pass
> nullptr in case of "please simply do a check, but do not build
> capnp-data".  Is this possible at all?
>
> If not, are there any suggestions you have for me how to provide such
> functionality?
>
> Thanks a lot in advance,
> Stefan
>
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