DispatchQueue

Undocumented

  • 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

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

    Parameters

    token

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

    Block to execute once