NAME

       io_submit - Submit io requests

SYNOPSIS

       #include <errno.h>

       #include <libaio.h>

       int io_submit(io_context_t ctx, long nr, struct iocb *iocbs[]);

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

DESCRIPTION

       io_submit() submits nr iocbs for processing for a given io context ctx.

       The  io_submit()  function  can  be  used to enqueue an arbitrary number of read and write
       requests at one time.  The requests can all be meant for the same file, all for  different
       files or every solution in between.

       io_submit()  gets the nr requests from the array pointed to by iocbs.  The operation to be
       performed is determined by the aio_lio_opcode member in each element of  iocbs.   If  this
       field is IO_CMD_PREAD a read operation is enqueued, similar to a call of io_prep_pread for
       this element of the array (except that the way the termination is signalled is  different,
       as we will see below).  If the aio_lio_opcode member is IO_CMD_PWRITE a write operation is
       enqueued.  Otherwise the aio_lio_opcode must be IO_CMD_NOP in which case this  element  of
       iocbs is simply ignored.  This ``operation'' is useful in situations where one has a fixed
       array of struct iocb elements from which only a few need to be handled at a time.  Another
       situation  is  where  the io_submit(3) call was canceled before all requests are processed
       and the remaining requests have to be reissued.

       The other members of each element of the array  pointed  to  by  iocbs  must  have  values
       suitable  for  the  operation  as  described in the documentation for io_prep_pread(3) and
       io_prep_pwrite(3) above.

       The function returns immediately after having enqueued  all  the  requests.   On  success,
       io_submit()  returns  the  number  of  iocbs submitted successfully.  Otherwise, -error is
       return, where error is one of the Exxx values defined in the Errors section.

       If an error is detected, then the behavior is undefined.

       Simultaneous asynchronous operations using the same iocb produce undefined results.

ERRORS

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

       EINVAL ctx refers to an uninitialized 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_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_set_callback(3), errno(3).