dispatch_io_handler_t
A handler block used to process operations on a dispatch I/O channel.
Declaration
typedef void (^)(_Bool, NSObject<OS_dispatch_data> *, int) dispatch_io_handler_t;Discussion
The parameters of a dispatch I/O handler are as follows:
done- A flag indicating whether the operation is complete.data- The data object to be handled. This object is retained by the system for the duration of the handler’s execution and is released when the handler block returns.error- The error number (if any) reported for the operation. An error number of0typically indicates the operation was successful.