lio_listio

LIO_LISTIO(3)              Linux Programmer's Manual             LIO_LISTIO(3)

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 de-
       scribed 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  com-
                   plete,  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  un-
       specified  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 con-
       trol  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  opera-
       tions  have completed successfully.  Otherwise, -1 is returned, and er-
       rno 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 op-
       erations  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.

       EINTR  mode was LIO_WAIT and a signal was caught before all I/O  opera-
              tions  completed;  see  signal(7).  (This may even be one of the
              signals used for asynchronous I/O completion notification.)

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

       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_lis-
       tio() 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.

ATTRIBUTES
       For  an  explanation  of  the  terms  used  in  this  section,  see at-
       tributes(7).

       +-------------+---------------+---------+
       |Interface    | Attribute     | Value   |
       +-------------+---------------+---------+
       |lio_listio() | Thread safety | MT-Safe |
       +-------------+---------------+---------+

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

NOTES
       It is a good idea to zero out the control blocks before use.  The  con-
       trol  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_sus-
       pend(3), aio_write(3), aio(7)

COLOPHON
       This page is part of release 5.05 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.

                                  2017-09-15                     LIO_LISTIO(3)