[swift-users] C interop: passing null pointers to unwrapped unsafe pointers

Ingo Maier ingoem at gmail.com
Sat Oct 8 03:50:08 CDT 2016

Oh thanks, I fundamentally misunderstood how unwrapped optionals work.

On Fri, Oct 7, 2016 at 6:25 PM, Joe Groff <jgroff at apple.com> wrote:
>> On Oct 7, 2016, at 7:02 AM, Ingo Maier via swift-users <swift-users at swift.org> wrote:
>> Is there a way in Swift 3 to pass a null pointer to a C function that
>> takes an implicitly unwrapped unsafe pointer? I understand that
>> pointer parameters in C that don't specify nullability are mapped to
>> implicitly unwrapped pointers in Swift 3. Since it's not uncommon for
>> existing unannotated C APIs to accept null pointers, I assume there
>> has to be a way other than creating my own bridge functions in C. I
>> hope I am not wrong.
>> I am a bit surprised that I couldn't find an answer to this, neither
>> on this list nor on stackoverflow, as I presume I am not the only one
>> with this problem. Sorry, if I missed something.
> An implicitly unwrapped Optional is still an Optional. You can use `nil` to pass a null pointer.
> -Joe

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