> On Apr 18, 2017, at 09:11 , Joe Groff <jgr...@apple.com> wrote:
>
>
>> On Apr 17, 2017, at 6:19 PM, Rick Mann via swift-users
>> <swift-users@swift.org> wrote:
>>
>> I'm trying to make a module out of a C library and header file. It has at
>> least one empty struct:
>>
>> struct lgs_context_t {};
>>
>> and a function:
>>
>> LGS_EXPORT struct lgs_context_t* lgs_init(const lgs_context_params_t*
>> params);
>>
>> Swift sees the function, I can call it and assign the result to a variable,
>> but Xcode (as usual) fails to show me what it thinks the type is. So I can't
>> declare a class member to hold the returned pointer.
>>
>> I'm trying to declare the member like this:
>>
>> var ctx: lgs_context_t? // Use of undeclared type
>> 'lgs_context_t'
>>
>> I finally tried calling it like this:
>>
>> let ctx: UnsafeMutablePointer = lgs_init(...)
>>
>> and the resulting error message gave me OpaquePointer. But couldn't it just
>> typealias lgs_context_t to OpaquePointer?
>>
>> Is there any way to do this in the modulemap?
>>
>> Thanks!
>
> The compiler uses OpaquePointer for pointers to incomplete types in C. It
> sounds like you left lgs_context_t declared but not defined in your header,
> in other words you wrote 'struct lgs_context_t;' without braces. If it were
> truly defined to be empty, then the type should have been imported.
It's defined with the braces (and nothing inside them).
--
Rick Mann
rm...@latencyzero.com
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