سؤال

Can I have a static pointer that is weak in objective-c? I know it compiles, but I want to know if it will behave as I expect a weak pointer to behave.

__weak static HMFSomeClass *weakStaticPointer;
هل كانت مفيدة؟

المحلول

Yes, that behaves like a proper weak pointer:

__weak static NSObject *weakStaticPointer;

int main(int argc, char * argv[])
{
    @autoreleasepool {
        NSObject *obj = [NSObject new];
        weakStaticPointer = obj;
        NSLog(@"%@", weakStaticPointer);
        obj = nil; // object is deallocated -> weak pointer is set to nil
        NSLog(@"%@", weakStaticPointer);
    }
    return 0;
}

Output:

<NSObject: 0x100106a50>
(null)

Also I cannot find any restrictions in the Clang/ARC documentation that forbids a weak pointer to be static.

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