DispatchQueue

public extension DispatchQueue
  • 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 multithreaded calls.

    Declaration

    Swift

    class func once(token: String, block: () -> Void)

    Parameters

    token

    A unique reverse DNS style name such as com.vectorform. or a GUID.

    block

    The block to execute once.