How to check the NULL value in NSString in iOS?

Question

I have an NSString and I want to check if it has a NULL value. If it does, then the if condition should execute. Else it should execut

Answer 1

#define SAFESTRING(str) ISVALIDSTRING(str) ? str : @""
#define ISVALIDSTRING(str) (str != nil && [str isKindOfClass:[NSNull class]] == NO)
#define VALIDSTRING_PREDICATE [NSPredicate predicateWithBlock:^(id evaluatedObject, NSDictionary *bindings) {return (BOOL)ISVALIDSTRING(evaluatedObject);}]

SAFESTRING("PASS_OBJECT_HERE");