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NAME

       lio_listio - initiate a list of I/O requests

SYNOPSIS

       #include <aio.h>

       int lio_listio(int mode, struct aiocb *const aiocb_list[],
                      int nitems, struct sigevent *sevp);

       Link with -lrt.

DESCRIPTION

       The   lio_listio()  function  initiates  the  list  of  I/O  operations
       described by the array aiocb_list.

       The mode operation has one of the following values:

       LIO_WAIT    The call blocks until all  operations  are  complete.   The
                   sevp argument is ignored.

       LIO_NOWAIT  The  I/O  operations are queued for processing and the call
                   returns immediately.  When  the  I/O  operations  complete,
                   asynchronous  notification occurs, as specified by the sevp
                   argument; see sigevent(7) for details.  If sevp is NULL, no
                   asynchronous notification occurs.

       The  aiocb_list  argument  is  an array of pointers to aiocb structures
       that describe I/O operations.  These  operations  are  executed  in  an
       unspecified order.  The nitems argument specifies the size of the array
       aiocb_list.  NULL pointers in aiocb_list are ignored.

       In each control block in aiocb_list, the aio_lio_opcode field specifies
       the I/O operation to be initiated, as follows:

       LIO_READ  Initiate  a read operation.  The operation is queued as for a
                 call to aio_read(3) specifying this control block.

       LIO_WRITE Initiate a write operation.  The operation is queued as for a
                 call to aio_write(3) specifying this control block.

       LIO_NOP   Ignore this control block.

       The  remaining  fields  in each control block have the same meanings as
       for aio_read(3) and aio_write(3).   The  aio_sigevent  fields  of  each
       control  block  can be used to specify notifications for the individual
       I/O operations (see sigevent(7)).

RETURN VALUE

       If mode is LIO_NOWAIT, lio_listio() returns 0 if all I/O operations are
       successfully  queued.   Otherwise,  -1 is returned, and errno is set to
       indicate the error.

       If mode is LIO_WAIT,  lio_listio()  returns  0  when  all  of  the  I/O
       operations have completed successfully.  Otherwise, -1 is returned, and
       errno is set to indicate the error.

       The return status from lio_listio() provides information only about the
       call  itself,  not about the individual I/O operations.  One or more of
       the I/O operations may fail, but this does not prevent other operations
       completing.   The status of individual I/O operations in aiocb_list can
       be determined using aio_error(3).  When an operation has completed, its
       return  status  can  be  obtained  using aio_return(3).  Individual I/O
       operations can fail  for  the  reasons  described  in  aio_read(3)  and
       aio_write(3).

ERRORS

       The lio_listio() function may fail for the following reasons:

       EAGAIN Out of resources.

       EAGAIN The number of I/O operations specified by nitems would cause the
              limit AIO_MAX to be exceeded.

       EINVAL mode is invalid, or nitems exceeds the limit AIO_LISTIO_MAX.

       EINTR  mode was LIO_WAIT  and  a  signal  was  caught  before  all  I/O
              operations completed.  (This may even be one of the signals used
              for asynchronous I/O completion notification.)

       EIO    One of more of the operations specified  by  aiocb_list  failed.
              The  application  can  check  the status of each operation using
              aio_return(3).

       If lio_listio() fails with the error EAGAIN, EINTR, or EIO,  then  some
       of   the   operations  in  aiocb_list  may  have  been  initiated.   If
       lio_listio()  fails  for  any  other  reason,  then  none  of  the  I/O
       operations has been initiated.

VERSIONS

       The lio_listio() function is available since glibc 2.1.

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008.

NOTES

       It  is  a  good  idea  to  zero out the control blocks before use.  The
       control blocks must not be changed while  the  I/O  operations  are  in
       progress.  The buffer areas being read into or written from must not be
       accessed during the operations or undefined  results  may  occur.   The
       memory areas involved must remain valid.

       Simultaneous I/O operations specifying the same aiocb structure produce
       undefined results.

SEE ALSO

       aio_cancel(3),     aio_error(3),      aio_fsync(3),      aio_return(3),
       aio_suspend(3), aio_write(3), aio(7)

COLOPHON

       This  page  is  part of release 3.35 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://man7.org/linux/man-pages/.

                                  2010-10-20                     LIO_LISTIO(3)