What is atomic and Nonatomic in Objective C?
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.
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 Nonatomic strong?
In non-ARC code strong is just a synonym for retain. A variable maintains a strong reference to an object only as long as that variable is in scope, or until it is reassigned to another object or nil. Example.
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 and when to use weak?
readonly. As far as I know, strong and retain are synonyms, so they do exactly the same. Then the weak is almost like assign , but automatically set to nil after the object, it is pointing to, is deallocated. That means, you can simply replace them.
What is Nonatomic Objective-C?
thread unsafe mode
Nonatomic means “thread unsafe mode” and is (in a word) now totally irrelevant.
What does atomic mean in C?
Atomicity. In computer programming, an operation done by a computer is considered atomic if it is guaranteed to be isolated from other operations that may be happening at the same time. Put another way, atomic operations are indivisible.
What atomic value means?
An atomic value is a value that cannot be divided. For example, in the table shown below, the values in the [Color] column in the first row can be divided into “red” and “green”, hence [TABLE_PRODUCT] is not in 1NF.
What is the difference between copy and Link?
“Copy” will create a new product with the same info as the original, in the new category and independent of the original product. “Link” will create a reference from the new category to the original product, so you can make future changes once (in the master category) and have it up to date in all places.