Cannot convert value of type 'CFString' to expected argument type 'UnsafePointer<Void>' (aka 'UnsafePointer<()>')

问题

I am getting a build error, when I define the line

 let runFont : CTFontRef = CFDictionaryGetValue(CTRunGetAttributes(run), kCTFontAttributeName)

And the error is: Cannot convert value of type 'CFString' to expected argument type 'UnsafePointer' (aka 'UnsafePointer<()>')

回答1:

Try

let runFont = unsafeBitCast(CFDictionaryGetValue(CTRunGetAttributes(run), unsafeBitCast(kCTFontAttributeName, UnsafePointer<Void>.self)), CTFontRef.self)

回答2:

Swift 3 version of @vadian answer:

let runFont = unsafeBitCast(CFDictionaryGetValue(CTRunGetAttributes(run), unsafeBitCast(kCTFontAttributeName, to: UnsafeRawPointer.self)), to: CTFont.self)

来源：https://stackoverflow.com/questions/36310251/cannot-convert-value-of-type-cfstring-to-expected-argument-type-unsafepointer