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 all of 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 3.54 of the Linux man-pages project.  A  description  of  the
       project,     and    information    about    reporting    bugs,    can    be    found    at
       http://www.kernel.org/doc/man-pages/.

                                            2012-05-08                              LIO_LISTIO(3)