io_prep_pread(3) [debian man page]

io_prep_pread(3)						       Linux							  io_prep_pread(3)

NAME

       io_prep_pread - Set up asynchronous read

SYNOPSYS

       #include <errno.h>

       #include <libaio.h>

       inline void io_prep_pread(struct iocb *iocb, int fd, void *buf, size_t count, long long offset);
       "

       struct iocb {
	    void      *data;
	    unsigned  key;
	    short	   aio_lio_opcode;
	    short	   aio_reqprio;
	    int       aio_fildes;
       };

DESCRIPTION

       io_prep_pread is an inline convenience function designed to facilitate the initialization of the iocb for an asynchronous read operation.

       The  first iocb->u.c.nbytes = count bytes of the file for which iocb->aio_fildes = fd is a descriptor are written to the buffer starting at
       iocb->u.c.buf = buf.  Reading starts at the absolute position ioc->u.c.offset = offset in the file.

       This function returns immediately. To schedule the operation, the function io_submit must be called.

       Simultaneous asynchronous operations using the same iocb produce undefined results.

RETURN VALUES

       None.

ERRORS

       None.

SEE ALSO

       io(3),  io_cancel(3),   io_fsync(3),   io_getevents(3),	 io_prep_fsync(3),   io_prep_pwrite(3),   io_queue_init(3),   io_queue_release(3),
       io_queue_run(3), io_queue_wait(3), io_set_callback(3), io_submit(3), errno(3).

Linux 2.4							    2009-06-10							  io_prep_pread(3)

io_fsync(3)							       Linux							       io_fsync(3)

NAME

       io_fsync - Synchronize a file's complete in-core state with that on disk

SYNOPSYS

       #include <errno.h>

       #include <libaio.h>

       int io_fsync(io_context_t ctx, struct iocb *iocb, io_callback_t cb, int fd);

       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

       When dealing with asynchronous operations it is sometimes necessary to get into a consistent state.  This would mean for AIO that one wants
       to know whether a certain request or a group of request were processed.	This could be done by waiting for the  notification  sent  by  the
       system after the operation terminated, but this sometimes would mean wasting resources (mainly computation time).

       Calling	this  function	forces	all  I/O  operations  operating  queued  at the time of the function call operating on the file descriptor
       iocb->io_fildes into the synchronized I/O completion state .  The io_fsync function returns immediately but the	notification  through  the
       method  described in io_callback will happen only after all requests for this file descriptor have terminated and the file is synchronized.
       This also means that requests for this very same file descriptor which are queued after the synchronization request are not affected.

RETURN VALUES

       Returns 0, otherwise returns errno.

ERRORS

       EFAULT iocbs referenced data outside of the program's accessible address space.

       EINVAL ctx refers to an unitialized aio context, the iocb pointed to by iocbs contains an improperly initialized iocb,

       EBADF  The iocb contains a file descriptor that does not exist.

       EINVAL The file specified in the iocb does not support the given io operation.

SEE ALSO

       io(3),  io_cancel(3),  io_getevents(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_set_callback(3), io_submit(3), errno(3).

Linux 2.4							    2009-06-10							       io_fsync(3)