How to call Objective-C code from Swift?

Tutorial on how to use Objective-C Classes in Swift and visa versa
06 September 2017   16641

Let's consider two different ways of calling Obj-C code from Swift.

Using Objective-C Classes in Swift

Step 1: Add Objective-C Implementation -- .m

Add a .m file to your class, and name it CustomObject.m.

Step 2: Add Bridging Header

When adding your .m file, you'll receive a promt with Yes, No and Cancel buttons. Hit Yes.

Step 3: Add Objective-C Header -- .h

Add another .h file and name it CustomObject.h.

Step 4: Build your Objective-C Class

In CustomObject.h

#import <Foundation/Foundation.h>

@interface CustomObject : NSObject

@property (strong, nonatomic) id someProperty;

- (void) someMethod;


In CustomObject.m

#import "CustomObject.h"

@implementation CustomObject 

- (void) someMethod {
    NSLog(@"SomeMethod Ran");


Step 5: Add Class to Bridging-Header

In YourProject-Bridging-Header.h

#import "CustomObject.h"

Step 6: Use your Object

In SomeSwiftFile.swift:

var instanceOfCustomObject: CustomObject = CustomObject()
instanceOfCustomObject.someProperty = "Hello World"

There is no need to import explicitly; that's what the bridging header is for.

Using Swift Classes in Objective-C

Now, let's go visa versa and learn how to use Swift Classes in Objective-C.

Step 1: Create New Swift Class

Add a .swift file to your project, and name it MySwiftObject.swift.

In MySwiftObject.swift:

import Foundation

class MySwiftObject : NSObject {

    var someProperty: AnyObject = "Some Initializer Val"

    init() {}

    func someFunction(someArg:AnyObject) -> String {
        var returnVal = "You sent me \(someArg)"
        return returnVal

Step 2: Import Swift Files to ObjC Class

In SomeRandomClass.m:

#import "<#YourProjectName#>-Swift.h"

The file:<#YourProjectName#>-Swift.h should already be created automatically in your project, even if you can not see it.

Step 3: Use your class

MySwiftObject * myOb = [MySwiftObject new];
NSLog(@"MyOb.someProperty: %@", myOb.someProperty);
myOb.someProperty = @"Hello World";
NSLog(@"MyOb.someProperty: %@", myOb.someProperty);
NSString * retString = [myOb someFunction:@"Arg"];
NSLog(@"RetString: %@", retString);

Google to Unveil macOS Vulnerability

It is associated with the implementation of a copy-on-write mechanism in the system
05 March 2019   743

Specialists at Google Project Zero found a vulnerability in the macOS kernel. It is associated with the implementation of a copy-on-write mechanism in the system, used for operating with copies of memory. An attacker can change files in a mounted macOS file system image without the file system warning and get the execution of malicious code.

This copy-on-write behavior works not only with anonymous memory, but also with file mappings. This means that, after the destination process has started reading from the transferred memory area, memory pressure can cause the pages holding the transferred memory to be evicted from the page cache. Later, when the evicted pages are needed again, they can be reloaded from the backing filesystem.

Google Project Zero team

The Google Project Zero team reported to Apple about their discovery back in November last year, but for 90 days the company failed to solve the problem, so the experts published information and the PoC-code exploit.