'self' used before super.init call in swift 3.0 - swift3

Question

I have sub class of OutputStream. In that I have two init() methods one have prefix word convenience.
Here is my code :
class FileOutputStream : OutputStream
{
fileprivate let filepath:URL
fileprivate let channel:DispatchIO!
convenience init?(filename:String) {
let pathURL = FileManager.default.urls(for: FileManager.SearchPathDirectory.documentDirectory, in:.userDomainMask).first!.appendingPathComponent(filename)
self.init(filepath:pathURL)
}
init?(filepath f:URL) {
self.filepath = f
//if let path = f.path,
if let cpath = (f.path).cString(using: String.Encoding.utf8) {
let outputflag:Int32 = O_CREAT | O_WRONLY // create, write-only
let mode:mode_t = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH // permissions: u+rw, g+r, o+r
self.channel = DispatchIO(type: DispatchIO.StreamType.stream, path:cpath, oflag:outputflag,mode: mode, queue: DispatchQueue.global(qos: DispatchQoS.QoSClass.background)) { (errcode:Int32) -> Void in
if errcode != 0 {
print("FileOutputStream: error creating io channel")
}
}
}
else {
self.channel = nil
return nil
}
}
func write(_ string: String) {
if let dataString = string.data(using: String.Encoding.utf8) {
dataString.withUnsafeBytes {(bytes: UnsafePointer<UInt8>) -> Void in
var data = DispatchData.empty
data.append(bytes, count: dataString.count)
self.channel.write(offset: 0, data: data, queue: DispatchQueue.global(qos:.background), ioHandler: { (complete: Bool, data: DispatchData?, errorCode: Int32) in
//handle progress reporting here
if errorCode != 0 {
print("FileOutputStream: error writing data to channel")
}
})
}
}
}
deinit {
self.channel.close(flags: DispatchIO.CloseFlags.stop)
}
}
I am getting error
'self' used before super.init call
I have tried by writing
super.init()
in both method, at start of methods
at end of methods
only in second method
only in first method.
But still getting error. If anyone know, please help me.

Answer 1

Use super.init(url: f, append: false/true) at the end of your init?(filepath f:URL) method .
Your intializer must call designated intializer of super class..Call any of these init methods that is available in OutputStream class...
public init(toMemory: ())
public init(toBuffer buffer: UnsafeMutablePointer<UInt8>, capacity: Int)
#available(iOS 4.0, *)
public init?(url: URL, append shouldAppend: Bool)