CODEWITHSUNDEEP
c++objective-ciosmemory-management
Ali
Ali

Reputation: 2035

How do I retain a C++ object in Memory?

What is the object life cycle of a C++ object in an Objective-C class, and how do you keep it in memory?

I tried opaque structure, create instance, but that always leads to null.

Upvotes: 4

Views: 2637

Answers (2)

Ferruccio
Ferruccio

Reputation: 100668

If your C++ object is going to have the same life-cycle as the Objective-C object which contains it, you can simply place the C++ object (not a pointer to it) in the Objective-C class:

@interface MyClass {
    CppObject myObject;
}
@end

Upvotes: 1

Jacob Relkin
Jacob Relkin

Reputation: 163268

You can own a C++ object in your Objective-C class by creating a new instance of your C++ class inside of your init method, assigning it to an ivar, then in -dealloc, call delete on the ivar:

@interface SomeClass : NSObject {
  SomeCPPClass *cpp_object;
}
@end

@implementation SomeClass 

- (id) init {
   self = [super init];
   if(self) {
      cpp_object = new SomeCPPClass();
   }
   return self;
}

- (void) dealloc {
  delete cpp_object;
  [super dealloc];
}

@end

Upvotes: 6

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