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).

Linux                                              2019-07-23                                       io_submit(3)