Question

I´m using a struct on Objective-C to store some data, something like this:

@interface Interface : NSObject
{
    // my Data
    struct Data
    {
        __unsafe_unretained BOOL isInit;
        __unsafe_unretained BOOL isRegister;
        __unsafe_unretained NSString* myValue;
        
       // Data() : isInit(false), isRegister(false), myValue(@"mYv4lue") {} // Constructor doesnt work
    };

    struct Data myData;  // Create Struct
}

But I can’t compile with a constructor. I want the values take some default value when I create the struct.

How can I do this?

Answer 1

Structs don’t have initializers, if you want to create a struct with a particular set of values you could write a function that returns creates and initialises it for you:

For example

struct Data {
        BOOL isInit;
        BOOL isRegister;
        NSString* myValue;
};

Data MakeInitialData () {
    data Data;
    data.isInit = NO;
    data.isRegister = NO;
    data.myValue = @"mYv4lue";

    return data;
}

now you can get a correctly set up struct with:

Data newData = MakeInitialData();

A note, though; you seem to be using ARC, which doesn’t work well with structs that have object pointers in them. The recommendation in this case is to just use a class instead of a struct.