Okay, I woke up after a good sleep and found that someone with the same question had already replied to me on Baozhan, so I’ll post it here... What I asked on Baozhan was why he used the address to communicate with NULL comparison, and then it was modified by someone. Why do we need to use a constant address to compare with NULL? Because that UIKey.....is indeed a constant Okay, here is the reply that I think solved my problem "Comparing the address of a constant (or function) to null is generally used to determine if the constant is defined.
You're getting the warning because the SDK that you're building against (minimum target version) has the constant defined, so it will always evaluate to true (the address won't be null). However, when run on a version of iOS that doesn't have the constant defined, it will not be true (the address will be null).
If you lowered the target version to a version below where the constant were defined, it would weakly link to that SDK, and you would no longer receive the warning.”
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Okay, I woke up after a good sleep and found that someone with the same question had already replied to me on Baozhan, so I’ll post it here... What I asked on Baozhan was why he used the address to communicate with NULL comparison, and then it was modified by someone. Why do we need to use a constant address to compare with NULL? Because that UIKey.....is indeed a constant
Okay, here is the reply that I think solved my problem "Comparing the address of a constant (or function) to null is generally used to determine if the constant is defined.
You're getting the warning because the SDK that you're building against (minimum target version) has the constant defined, so it will always evaluate to true (the address won't be null). However, when run on a version of iOS that doesn't have the constant defined, it will not be true (the address will be null).
If you lowered the target version to a version below where the constant were defined, it would weakly link to that SDK, and you would no longer receive the warning.”