`fileprivate` is one of the new Swift 3 access modifiers that replaces `private` in its meaning. `fileprivate` defines an entity (class, extension, property, ...) as private to everybody outside the source file it is declared in, but accessible to all entities in that source file.

`private` restricts the entity in the direct enclosing scope.


An argument to this function will bind to an rvalue reference:  

    void f(int &amp;&amp; i);

However, an argument to this function will bind to either an rvalue or an lvalue reference:  

    template &lt;typename T&gt;  
    void f(T &amp;&amp; t);
I&#39;ve often heard this referred to as a universal reference.    
I&#39;ve also heard it been called a forwarding reference.  
Do they mean the same thing?   
Is it only a forwarding reference if the function body calls `std::forward`?

Is there a difference between universal references and forwarding references?

In ReactJS, is there a way to determine if the website is being viewed on mobile or desktop? Because, depending on which device I would like to render different things.

Thank you

ReactJS: How to determine if the application is being viewed on mobile or desktop browser

I&#39;m starting in swift and opening a project created using swift2 from xcode 8 beta, the `private` modifier were changed to `fileprivate`. what does this keyword means? and how is different from `private` ?

What does &#39;fileprivate&#39; keyword means in Swift?

<p>I'm starting in swift and opening a project created using swift2 from xcode 8 beta, the <code>private</code> modifier were changed to <code>fileprivate</code>. what does this keyword means? and how is different from <code>private</code> ?</p>


Why are **implicitly unwrapped optionals** not unwrapped when using string interpolation in Swift 3?

**Example**:
Running the following code in the playground

    var str: String!
    str = &quot;Hello&quot;
    
    print(&quot;The following should not be printed as an optional: \(str)&quot;)

produces this output: 

    The following should not be printed as an optional: Optional(&quot;Hello&quot;)

Of course I can concatenate strings with the `+` operator but I&#39;m using string interpolation pretty much everywhere in my app which now doesn&#39;t work anymore due to this (bug?). 

Is this even a bug or did they intentionally change this behaviour with Swift 3?

Swift 3 incorrect string interpolation with implicitly unwrapped Optionals

`openURL` has been deprecated in Swift3.  Can anyone provide some examples of how the replacement `openURL:options:completionHandler:` works when trying to open an url?

how to open an URL in Swift3

I&#39;m getting `No such module` for Pods when I try to build the project. If I remove the code expecting this Pod, another &#39;No such module&#39; comes up for another Pod, which means every Pod must be affected. When I type `pod install` I get the following messages:

    [!] The X target overrides the `EMBEDDED_CONTENT_CONTAINS_SWIFT` build setting defined in `X’. This can lead to problems with the CocoaPods installation
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.

    [!] The `X` target overrides the `ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES` build setting defined in `X&#39;. This can lead to problems with the CocoaPods installation
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.

I get each of these for both the debug and release versions of my app and the two tests, so 12 messages in total.

I have set `Always Embed Swift Standard Libraries` and `EMBEDDED_CONTENT_CONTAINS_SWIFT` to `NO` and `YES` both in my Build Settings and this did nothing. I also added the following code to my Podfile and it didn&#39;t work either:

    post_install do |installer|
    installer.pods_project.targets.each do |target|
        target.build_configurations.each do |config|
            config.build_settings[&#39;ALWAYS_EMBED_SWIFT_STANDARD_LIBRARIES&#39;] = &#39;NO&#39;
        end
    end
    end

Errors after updating to Xcode 8: &quot;No such module&quot; and &quot;target overrides the `EMBEDDED_CONTENT_CONTAINS_SWIFT`build setting&quot;

It seems that for some reason Swift have chosen to make coding in it less readable by forcing users to remove completion handler parameter labels.  I have read the Swift discussion and still think it&#39;s a mistake.  At least they could have made it optional. 

When building using Xcode 8 - is there a way to force the compiler to use Swift 2.3 so I don&#39;t get these errors anymore? 
I have updated the option to use legacy Swift (under build settings) 
[![legacy support in xcode][1]][1]
but I still seem to get this error: 

&gt;  Function types cannot have argument label &#39;isloggedIn&#39;; use &#39;_&#39;
&gt; instead

[![error Xcode 8][2]][2]

How can I keep my labels in my completion handlers?


  [1]: http://i.stack.imgur.com/A4WlH.jpg
  [2]: http://i.stack.imgur.com/zZKtZ.jpg

Xcode 8 :function types cannot have argument label breaking my build

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {}

I want `deviceToken` to string

but:

    let str = String.init(data: deviceToken, encoding: .utf8)

`str` is `nil`

swift 3.0 

how can I let `data` to `string` ?


 https://stackoverflow.com/questions/37956482/registering-for-push-notifications-in-xcode-8-swift-3-0
not working and the answer is a few months ago, I had tried it:

[![enter image description here][1]][1]

and print:

[![enter image description here][2]][2]




  [1]: http://i.stack.imgur.com/tcqjQ.png
  [2]: http://i.stack.imgur.com/WKD6I.png

swift 3.0 Data to String?

I would like to test some private methods using GoogleTest.

&lt;!-- language: lang-c++ --&gt;

    class Foo
    {
    private:
        int bar(...)
    }

GoogleTest allows a couple of ways of doing this.

**OPTION 1**

With *FRIEND_TEST*:

&lt;!-- language: lang-c++ --&gt;

    class Foo
    {
    private:
        FRIEND_TEST(Foo, barReturnsZero);
        int bar(...);
    }

    TEST(Foo, barReturnsZero)
    {
        Foo foo;
        EXPECT_EQ(foo.bar(...), 0);
    }


This implies to include &quot;gtest/gtest.h&quot; in the production source file.

**OPTION 2**

Declare a *test fixture* as a friend to the class and define accessors in the fixture:

&lt;!-- language: lang-c++ --&gt;

    class Foo
    {
        friend class FooTest;
    private:
        int bar(...);
    }

    class FooTest : public ::testing::Test
    {
    protected:
        int bar(...) { foo.bar(...); }
    private:
        Foo foo;
    }

    TEST_F(FooTest, barReturnsZero)
    {
        EXPECT_EQ(bar(...), 0);
    }

**OPTION 3**

The *Pimpl idiom*.


For details: [Google Test: Advanced guide][1].

Are there any other ways to test private methods? What are some pros and cons of each option?




  [1]: https://github.com/google/googletest/blob/master/googletest/docs/advanced.md#testing-private-code

What is the best way of testing private methods with GoogleTest?

In TypeScript 3.8+, what are the differences between using the `private` keyword to mark a member private:

```ts
class PrivateKeywordClass {
    private value = 1;
}
```

And using the `#` private fields [proposed for JavaScript](https://github.com/tc39/proposal-class-fields#private-fields):

```ts
class PrivateFieldClass {
    #value = 1;
}
```

Should I prefer one over the other?


What are the differences between the private keyword and private fields in TypeScript?

I have some protocols

**LoginStrategy**

    public protocol LoginStrategy {
        func login(_ viewController: UIViewController)
        func getUserInfo(withCompletionHandler completionHandler: @escaping (_ userInfo: [String: Any]?) -&gt; ())
        func createLoginButton(_ frame: CGRect, withCompletionHandler completionHandler: @escaping (_ loginButton: UIView) -&gt; ())
        func getUserId() -&gt; String
    }

and two classes:

**LoginProvider**

    public class LoginProvider {
        
        public let strategy: LoginStrategy
        
        public func login(_ viewController: UIViewController) {
            return self.strategy.login(viewController)
        }
        
        public func getUserInfo(withCompletionHandler completionHandler: @escaping (_ userInfo: [String: Any]?) -&gt; ()) {
            return self.strategy.getUserInfo(withCompletionHandler: completionHandler)
        }
        
        public func createLoginButton(_ frame: CGRect, withCompletionHandler completionHandler: @escaping (_ loginButton: UIView) -&gt; ()) {
            return self.strategy.createLoginButton(frame, withCompletionHandler: completionHandler)
        }
        
        public func getUserId() -&gt; String {
            return self.strategy.getUserId()
        }
        
        public init(strategy: LoginStrategy) {
            self.strategy = strategy
        }
        
    }

**FacebookLoginStrategy**

    import Foundation
    import FacebookCore
    import FacebookLogin
    
    public class FacebookLoginStrategy: LoginStrategy {
        
        public var grantedPermissions: Set&lt;Permission&gt;? = nil
    
        public var declinedPermissions: Set&lt;Permission&gt;? = nil
        
        public var userId: String = &quot;&quot;
        
        public func login(_ viewController: UIViewController) {
            let loginManager = LoginManager()
            let permissions: [ReadPermission] = [.publicProfile, .userFriends, .email]
            loginManager.logIn(permissions, viewController: viewController) { loginResult in
                switch loginResult {
                case .failed(let error):
                    print(error)
                case .cancelled:
                    print(&quot;User cancelled login.&quot;)
                case .success(let grantedPermissions, let declinedPermissions, let accessToken):
                    self.userId = accessToken.userId ?? &quot;&quot;
                    self.grantedPermissions = grantedPermissions
                    self.declinedPermissions = declinedPermissions
                    print(&quot;Logged in!&quot;)
                }
            }
        }
        
        public func getUserId() -&gt; String {
            return userId
        }
        
        public func getUserInfo(withCompletionHandler completionHandler: @escaping (_ userInfo: [String: Any]?) -&gt; ()) {
            let request = GraphRequest(graphPath: &quot;me&quot;, parameters: [&quot;fields&quot;:&quot;email, name&quot;], accessToken: AccessToken.current, httpMethod: .GET, apiVersion: FacebookCore.GraphAPIVersion.defaultVersion)
            request.start { (response, result) in
                switch result {
                case .success(let value):
                    print(value.dictionaryValue)
                    completionHandler(value.dictionaryValue)
                case .failed(let error):
                    print(error)
                }
            }
        }
    
        public func createLoginButton(_ frame: CGRect, withCompletionHandler completionHandler: @escaping (_ loginButton: UIView) -&gt; ()) {
            let permissions: [ReadPermission] = [.publicProfile, .userFriends, .email]
            let loginButton = LoginButton(readPermissions: permissions)
            loginButton.frame = frame
            completionHandler(loginButton)
        }
    }

In my **ViewController**:

When I use:

    let facebookLoginProvider = LoginProvider(strategy: FacebookLoginStrategy())

It says:

&gt; &#39;FacebookLoginStrategy&#39; is inaccessable due to &#39;internal&#39; protection
&gt; level


Initializer is inaccessable due to &#39;internal&#39; protection level

I have seen some references refer to a access modifier in Java called `private protected` (both words together):

    private protected someMethod() {

    }

One of the pages I found referring to this is [here][1]. My school lesson also referred to this access modifier (and said it exists). Using it, however, results in an error in the Java language.

I tried with both variables and methods and I&#39;m pretty sure it doesn&#39;t exist, but I want an explanation of what happened. Was it considered, then rejected? Or did it get removed in a newer version of Java?

[1]:https://www.cs.princeton.edu/courses/archive/spr96/cs333/java/tutorial/java/javaOO/methodaccess.html

Edit: I am not looking for info about the `protected` keyword.

Does Java have a &quot;private protected&quot; access modifier?

I&#39;ve recently upgraded to Intellij IDEA 2017.2 and access modifier icons disappeared from my file tree... How to get them back?

[![][1]][1]


  [1]: https://i.stack.imgur.com/gr70C.png

How to show access modifiers for classes in IntelliJ IDEA?

[C# 7.2 introduces the private protected modifier][1]. 

I&#39;ve always protected access to fields with properties, allowing access via the Get/Set methods as I typically don&#39;t want the internal state of my object modified by anything other than my own class.

I&#39;m trying to understand why the C# language team have added this feature. After an extensive search on google, and reading and watching the &#39;what&#39;s new&#39; media (I&#39;ve watched the [press release][2], [details][3] and [video by Mads Torgerson][4]), I am still none the wiser.

To me, this appears to allow a developer to break the Liskov Substitution principle, but this may be because I do not understand why this feature now exists.

I understand how it can be used, just not why - please can someone provide a real-world usage example rather than the contrived one in the MSDN documents?

  [1]: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/private-protected
  [2]: https://blogs.msdn.microsoft.com/dotnet/2017/11/15/welcome-to-c-7-2-and-span/?utm_source=vs_developer_news&amp;utm_medium=referral
  [3]: https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7-2
  [4]: https://channel9.msdn.com/events/Connect/2017/T122

Content Type	Original Author	Original Content on Stackoverflow
Question	Nathaniel	View Question on Stackoverflow
Solution 1 - Swift	Jans	View Answer on Stackoverflow

What does 'fileprivate' keyword means in Swift?

Swift Problem Overview

Swift Solutions

Solution 1 - Swift

ReactJS: How to determine if the application is being viewed on mobile or desktop browser

Is there a difference between universal references and forwarding references?

Attributions