SO Answer 2

You also need to take care with objects passed by reference. The following code will work:

NSError *error;
BOOL OK = [myObject performOperationWithError:&error];
if (!OK) {
    // Report the error.
    // ...

However, the error declaration is implicitly:

NSError * __strong e;

and the method declaration would typically be:

-(BOOL)performOperationWithError:(NSError * __autoreleasing *)error;

The compiler therefore rewrites the code:

NSError * __strong error;
NSError * __autoreleasing tmp = error;
BOOL OK = [myObject performOperationWithError:&tmp];
error = tmp;
if (!OK) {
    // Report the error.
    // ...