io_prep_pwrite(3) Linux io_prep_pwrite(3)NAME
io_prep_pwrite - Set up iocb for asynchronous writes
SYNOPSYS
#include <errno.h>
#include <libaio.h>
inline void io_prep_pwrite(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_write is a convenicence function for setting up parallel writes.
The first iocb->u.c.nbytes = count bytes of the file for which iocb->aio_fildes = fd is a descriptor are written from the buffer starting
at iocb->u.c.buf = buf. Writing 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_pread(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_pwrite(3)
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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)
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