abstract:In computer programming, an opaque pointer is a special case of an opaque data type, a datatype declared to be a pointer to a record or data structure of some unspecified type.
The iocb argument canusually be treated as an opaque cookie used by theAIOsubsystem; ifyou need the structfilepointer for this filedescriptor, however, you can find it as iocb->ki_filp.