Swift 2 无法使用类型的参数列表调用 'FSEventStreamCreate'

Question

使用 Swift 2 和 Xcode 7 beta 2（内部版本：7A121l）我使用 FSEventStream API 和 @convention(c) 得到这个编译错误。

任何建议都很棒，谢谢！

internal class FileSystem {

init () {

    let allocator: CFAllocator? = kCFAllocatorDefault

    // Create FSEventStream and return valid FSEventStreamRef
    // Alias FSEventStreamCallback - CFunction

    typealias FSEventStreamCallback = @convention(c) (ConstFSEventStreamRef, UnsafeMutablePointer<Void>, UInt, UnsafeMutablePointer<Void>, UnsafePointer<FSEventStreamEventFlags>, UnsafePointer<FSEventStreamEventId>) -> Void

    let callback: FSEventStreamCallback = {
        (streamRef, clientCallBackInfo, numEvents, eventPaths, eventFlags, eventIds) -> Void in
        print ("changed")
        // handle file event
    }

    let context: UnsafeMutablePointer<FSEventStreamContext> = nil
    let pathsToWatch: CFArray = [NSHomeDirectory() + "/Dir"]
    let sinceWhen: FSEventStreamEventId = UInt64(kFSEventStreamEventIdSinceNow)
    let latency: CFTimeInterval = 1.0
    let flags: FSEventStreamCreateFlags = UInt32(kFSEventStreamCreateFlagNone)

    let eventStream = FSEventStreamCreate(
        allocator,
        callback,
        context,
        pathsToWatch,
        sinceWhen,
        latency,
        flags
    )

    FSEventStreamScheduleWithRunLoop(eventStream, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode)
    FSEventStreamStart(eventStream)

}
}

Answer 1

您使用了错误的签名（UInt 不是 Int）：

typealias FSEventStreamCallback = @convention(c) (ConstFSEventStreamRef, UnsafeMutablePointer<Void>, Int, UnsafeMutablePointer<Void>, UnsafePointer<FSEventStreamEventFlags>, UnsafePointer<FSEventStreamEventId>) -> Void

编译正常：

init () {

    let allocator: CFAllocator? = kCFAllocatorDefault

    // Create FSEventStream and return valid FSEventStreamRef
    // Alias FSEventStreamCallback - CFunction
    typealias FSEventStreamCallback = @convention(c) (ConstFSEventStreamRef, UnsafeMutablePointer<Void>, Int, UnsafeMutablePointer<Void>, UnsafePointer<FSEventStreamEventFlags>, UnsafePointer<FSEventStreamEventId>) -> Void
    let callback: FSEventStreamCallback = {
        (streamRef, clientCallBackInfo, numEvents, eventPaths, eventFlags, eventIds) -> Void in
        print ("changed")
        // handle file event
    }


    let context: UnsafeMutablePointer<FSEventStreamContext> = nil
    let pathsToWatch: CFArray = [NSHomeDirectory() + "/Dir"]
    let sinceWhen: FSEventStreamEventId = UInt64(kFSEventStreamEventIdSinceNow)
    let latency: CFTimeInterval = 1.0
    let flags: FSEventStreamCreateFlags = UInt32(kFSEventStreamCreateFlagNone)

    let eventStream = FSEventStreamCreate(
        allocator,
        callback,
        context,
        pathsToWatch,
        sinceWhen,
        latency,
        flags
    )

    FSEventStreamScheduleWithRunLoop(eventStream, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode)
    FSEventStreamStart(eventStream)

}

Swift 2 无法使用类型的参数列表调用 'FSEventStreamCreate'

Swift 2 Cannot invoke 'FSEventStreamCreate' with an argument list of type

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