lio_listio(2) [freebsd man page]

LIO_LISTIO(2)						      BSD System Calls Manual						     LIO_LISTIO(2)

NAME

     lio_listio -- list directed I/O (REALTIME)

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <aio.h>

     int
     lio_listio(int mode, struct aiocb * const list[], int nent, struct sigevent *sig);

DESCRIPTION

     The lio_listio() function initiates a list of I/O requests with a single function call.  The list argument is an array of pointers to aiocb
     structures describing each operation to perform, with nent elements.  NULL elements are ignored.

     The aio_lio_opcode field of each aiocb specifies the operation to be performed.  The following operations are supported:

     LIO_READ	Read data as if by a call to aio_read(2).

     LIO_NOP	No operation.

     LIO_WRITE	Write data as if by a call to aio_write(2).

     If the mode argument is LIO_WAIT, lio_listio() does not return until all the requested operations have been completed.  If mode is
     LIO_NOWAIT, the requests are processed asynchronously, and the signal specified by sig is sent when all operations have completed.  If sig is
     NULL, the calling process is not notified of I/O completion.

     The order in which the requests are carried out is not specified; in particular, there is no guarantee that they will be executed in the
     order 0, 1, ..., nent-1.

RETURN VALUES

     If mode is LIO_WAIT, the lio_listio() function returns 0 if the operations completed successfully, otherwise -1.

     If mode is LIO_NOWAIT, the lio_listio() function returns 0 if the operations are successfully queued, otherwise -1.

ERRORS

     The lio_listio() function will fail if:

     [EAGAIN]		There are not enough resources to enqueue the requests.

     [EAGAIN]		The request would cause the system-wide limit AIO_MAX to be exceeded.

     [EINVAL]		The mode argument is neither LIO_WAIT nor LIO_NOWAIT, or nent is greater than AIO_LISTIO_MAX.

     [EINTR]		A signal interrupted the system call before it could be completed.

     [EIO]		One or more requests failed.

     In addition, the lio_listio() function may fail for any of the reasons listed for aio_read(2) and aio_write(2).

     If lio_listio() succeeds, or fails with an error code of EAGAIN, EINTR, or EIO, some of the requests may have been initiated.  The caller
     should check the error status of each aiocb structure individually by calling aio_error(2).

SEE ALSO

     aio_error(2), aio_read(2), aio_write(2), read(2), write(2), siginfo(3), aio(4)

STANDARDS

     The lio_listio() function is expected to conform to IEEE Std 1003.1-2001 (``POSIX.1'').

BSD
								 January 12, 2003							       BSD

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 complete, asyn-
		   chronous 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  asyn-
	      chronous 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_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.

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 3.44 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)