What is the difference between Retain & Assign?
Assign creates a reference from one object to another without increasing the source’s retain count. Retain creates a reference from one object to another and increases the retain count of the source object.
What is assign in Objective C?
assign -assign is the default and simply performs a variable assignment -assign is a property attribute that tells the compiler how to synthesize the property’s setter implementation -I would use assign for C primitive properties and weak for weak references to Objective-C objects.
What does @property do in Objective C?
The goal of the @property directive is to configure how an object can be exposed. If you intend to use a variable inside the class and do not need to expose it to outside classes, then you do not need to define a property for it. Properties are basically the accessor methods.
What’s a difference between copy and retain?
Retain increases the retain count of an object by 1 and takes ownership of an object. Whereas copy will copy the data present in the memory location and will assign it to the variable so in the case of copy you are first copying the data from a location assign it to the variable which increases the retain count.
What is the difference between retain and assign use previous answers?
What is Nonatomic in Objective C?
In Objective-C the implementation of an atomic property allows properties to be safely read and written from different threads. For nonatomic properties, the underlying pointer of a read value could be released when a new value is being written at the same time.
What is a non atomic attribute?
Non atomic properties has no guarantee regarding the returned value . It can be the correct value, a partially written value or even some garbage value. As most things that are not safe — this comes with enhanced speed of accessing this properties.
What does Nonatomic mean in Objective-C?
Nonatomic means multiple thread access the variable (dynamic type). Nonatomic is thread unsafe. But it is fast in performance. Nonatomic is NOT default behavior; we need to add nonatomic keyword in property attribute.
What is Nonatomic property in Objective C?
What is atomic Nonatomic?
Atomic means only one thread accesses the variable (static type). Atomic is thread-safe, but it is slow. Nonatomic means multiple threads access the variable (dynamic type). Nonatomic is thread-unsafe, but it is fast.
What is Nonatomic Objective-C?
Why do we use atomic and non atomic and what is default Behaviour?
Atomic:- is the default behavior. it will ensure the present process is completed by the CPU, before another process accesses the variable.it is not fast, as it ensures the process is completed entirelyNon-Atomic: – is NOT the default behavior.
What is the difference between atomic and nonatomic methods?
nonatomic : It specifies that accessors methods simply set or return a value directly, with no guarantee about what happens if that same value is accessed simultaneously from different threads. For this reason, it’s faster to access a nonatomic property than an atomic one.
Should I use atomic or nonatomic for iOS apps?
nonatomic vs. atomic – “atomic” is the default. Always use “nonatomic”. I don’t know why, but the book I read said there is “rarely a reason” to use “atomic”. (BTW: The book I read is the BNR “iOS Programming” book.)
What is nonatomic variable in Java?
nonatomic -Nonatomic means multiple thread access the variable (dynamic type). -Nonatomic is thread unsafe. -but it is fast in performance -Nonatomic is NOT default behavior,we need to add nonatomic keyword in property attribute. -it may result in unexpected behavior, when two different process (threads) access the same variable at the same time.