NAME
       io_set_callback - Set up io completion callback function
SYNOPSYS
       #include <errno.h>
       #include <libaio.h>
       static inline void io_set_callback(struct iocb *iocb, io_callback_t cb);
       struct iocb {
            void      *data;
            unsigned  key;
            short          aio_lio_opcode;
            short          aio_reqprio;
            int       aio_fildes;
       };
       typedef void (*io_callback_t)(io_context_t ctx, struct iocb *iocb, long res, long res2);
DESCRIPTION
       The   callback  is  not  done  if  the  caller  uses  raw  events  from
       io_getevents, only with the library helpers.
RETURN VALUES
       None.
ERRORS
       None.
SEE ALSO
       io(3), io_cancel(3),  io_fsync(3),  io_getevents(3),  io_prep_fsync(3),
       io_prep_pread(3),          io_prep_pwrite(3),         io_queue_init(3),
       io_queue_release(3), io_queue_run(3),  io_queue_wait(3),  io_submit(3),
       errno(3).