CODEWITHSUNDEEP
objective-cios8backwards-compatibilitytouch-id
CoderNinja
CoderNinja

Reputation: 571

How to check if a class or CFType is available in Objective-C

I am working in iOS8 right now and I wanted to check if the CFType 'SecAccessControlRef' is available. Since the app will support iOS 7, without a check, the app will crash. For a regular NSClass I would just use a check like 

if (NSClassFromString('SomeClass') == NULL)

but is there something similar for non NSClass items?

Upvotes: 1

Views: 155

Answers (2)

CRD
CRD

Reputation: 53000

Rather than testing for the type itself you can test for one of the functions that support the type. When a framework is weak-linked the address of C functions will be NULL if the framework is not present. For example you should be able to use something like:

BOOL isSecAccessControlRefAvailable = SecAccessControlCreateWithFlags != NULL;

See Using Weakly Linked Methods, Functions, and Symbols in Apple's SDK Compatibility Guide.

Upvotes: 4

Paul Cezanne
Paul Cezanne

Reputation: 8741

This isn't exactly what you want but I've used this for a similar type of question:

if (&kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly == NULL) {
    return NO; // must be on iOS7
}

Upvotes: 0

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