[swift-dev] Linux Swift API

Johannes WeiƟ johannesweiss at apple.com
Tue Jan 31 10:42:08 CST 2017


Hi Roman,

> On 31 Jan 2017, at 15:51, Roman Pastushkov via swift-dev <swift-dev at swift.org> wrote:
> 
> Hello everyone! Now i am trying (newbie) on Ubuntu Swift 3. I am trying to Read String from File Using FileHandle
> 
> import Foundation
> let filemgr = FileManager.default
> let filepath1 = "/home/roman/test"
> 
> let file: FileHandle? = FileHandle(forReadingAtPath: filepath1)
> 
> if file == nil {
>     print("File open failed")
> } else {
>     let databuffer = file?.readDataToEndOfFile
>     let String1 = String(databuffer, encoding: String.Encoding.utf8)
>     file?.closeFile()
>     print(String1)
> } 
> 
> But get error from compiler 
> /home/roman/swift/Sources/main.swift:11:19: error: 'init' has been renamed to 'init(describing:)'
>     let String1 = String(databuffer, encoding: String.Encoding.utf8)
>                   ^
> Swift.String:21:12: note: 'init' has been explicitly marked unavailable here
>     public init<T>(_: T)
>            ^

the error message is actually quite misleading. There are a few things that you need to correct:

you want the following constructor:
    String(data: databuffer, encoding: String.Encoding.utf8)
           ^^^^^

also, readDataToEndOfFile is a method, so you'll need to call it (`file?.readDataToEndOfFile()`) and lastly, databuffer will then have the type Data? (aka Optional<Data>) so you might want to use a 'if let'. The working program could then look like this:

import Foundation
let filemgr = FileManager.default
let filepath1 = "/home/roman/test"

let file: FileHandle? = FileHandle(forReadingAtPath: filepath1)

if file == nil {
    print("File open failed")
} else {
    if let databuffer = file?.readDataToEndOfFile() {
        let String1 = String(data: databuffer, encoding: String.Encoding.utf8)
        file?.closeFile()
        print("\(String1)")
    } else {
        print("File read failed")
    }   
}

HTH,
  Johannes


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