Question

How do I save a custom struct to NSUserDefaults?

struct Paging {
    NSInteger currentPage;
    NSInteger totalResults;
    NSInteger resultsPerPage;
};

typedef struct Paging Paging;

NSUserDefaults *userInfo = [NSUserDefaults standardUserDefaults];
[userInfo setStruct:paging forKey:@"paging"];
[userInfo synchronize];

The above code produces a run-time warning:
*** -[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value...

Answer 1

One way is to turn it into NSData

NSData* d = [NSData dataWithBytes: paging length: sizeof(paging)];

In this case your struct is pretty simple, so you might want to add a category to NSUserDefaults to save and restore it. I’d implement that by saving an NSDictionary with four NSNumbers. A bit more work, but it means your plist will be humanly readable.