Default value of an Objective-C struct and how to test

Question

I\'m trying to test if a property has been set yet. I know that with objects that I\'ve got:

CGRect ppGoalFrame;
LocalPlaySetup *localPlaySetup;

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Answer 1

All instance variables in an Objective-C class are initialized to zero. So all pointers are nil, numbers are 0, and structs are zeroed. Since the CGRect is a plain struct, it will be initialised to origin.x=0, origin.y=0, size.width=0, size.height=0.

So to test if your CGRect has been set, you need to compare it (by value) to zero. The CGRectIsEmpty function will do exactly this:

if (CGRectIsEmpty(ppGoalFrame))
{
    // ...
}