> On Jul 1, 2016, at 05:42 , Dan Loewenherz <d...@lionheartsw.com> wrote:
>
> What’s the Swift type signature on GDALOpen? My guess is that it’s returning
> a UnsafePointer<Void> or UnsafeMutablePointer<Void> type. Swift doesn’t
> currently handle nullability for C pointers (hence the “Unsafe” prefix).
> You’ll need to check the value at the pointer’s location manually.
It looks like this:
typealias GDALDatasetH = UnsafeMutablePointer<Void>
@warn_unused_result func GDALOpen(pszFilename: UnsafePointer<Int8>, _ eAccess:
GDALAccess) -> GDALDatasetH
Thanks for the clarification. It sure seems like Swift could easily check for
Unsafe Pointers with value == 0.
>
> Dan
>
> On Fri, Jul 1, 2016 at 2:59 AM, Rick Mann via swift-users
> <swift-users@swift.org> wrote:
> I have some Swift code (in Xcode 7.3) that's calling a C function in the GDAL
> library. It's declared like this:
>
> typedef void *GDALDatasetH;
> GDALDatasetH CPL_DLL CPL_STDCALL
> GDALOpen( const char *pszFilename, GDALAccess eAccess )
> CPL_WARN_UNUSED_RESULT;
>
> I'm calling it with code like this:
>
> class
> MyClass
> {
> func foo()
> {
> self.dataset = GDALOpen(path, GA_ReadOnly)
> }
>
> var dataset: GDALDatasetH?
> }
>
> But later code
>
> if let ds = self.dataset
> {
> print("dataset: \(ds)")
> }
>
> outputs this to the console:
>
> dataset: 0x0000000000000000
>
> This seems very broken.
>
> --
> Rick Mann
> rm...@latencyzero.com
>
>
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>
--
Rick Mann
rm...@latencyzero.com
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