DispatchQueue
public extension DispatchQueue
Extenstion to DispatchQueue
class.
-
Executes a block of code, associated with a unique token, only once. The code is thread safe and will only execute the code once even in the presence of multi-threaded calls.
Declaration
Swift
class func once(token: String, block: () -> Void)
Parameters
token
A unique name.
block
Block to execute once.