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
       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  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
       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 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
       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.

       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
       attributes(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 4.10 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/.



				  2016-10-08			 LIO_LISTIO(3)