\" $NetBSD: lio_listio.3,v 1.5 2011/08/12 23:40:43 wiz Exp $

\" $NetBSD: lio_listio.3,v 1.5 2011/08/12 23:40:43 wiz Exp $
\"
\" Copyright (c) 2003 Tim J. Robbins
\" All rights reserved.
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\" $FreeBSD: /repoman/r/ncvs/src/lib/libc/sys/lio_listio.2,v 1.6 2006/10/07 05:13:32 trhodes Exp $
\"
Dd August 12, 2011
Dt LIO_LISTIO 3
Os
Sh NAME
Nm lio_listio
Nd list directed I/O (REALTIME)
Sh LIBRARY
Lb librt
Sh SYNOPSIS
In aio.h
Ft int
Fo lio_listio
Fa "int mode"
Fa "struct aiocb * const list[]"
Fa "int nent"
Fa "struct sigevent *sig"
Fc
Sh DESCRIPTION
The
Fn lio_listio
function initiates a list of I/O requests with a single function call.
The
Fa list
argument is an array of pointers to
Vt aiocb
structures describing each operation to perform,
with
Fa nent
elements.
Dv NULL
elements are ignored.
Pp
The
Va aio_lio_opcode
field of each
Vt aiocb
specifies the operation to be performed.
The following operations are supported:
Bl -tag -width ".Dv LIO_WRITE" -offset indent
It Dv LIO_READ
Read data as if by a call to
Xr aio_read 3 .
It Dv LIO_NOP
No operation.
It Dv LIO_WRITE
Write data as if by a call to
Xr aio_write 3 .
El
Pp
If the
Fa mode
argument is
Dv LIO_WAIT ,
Fn lio_listio
does not return until all the requested operations have been completed.
If
Fa mode
is
Dv LIO_NOWAIT ,
the requests are processed asynchronously, and the signal specified by
Fa sig
is sent when all operations have completed.
If
Fa sig
is
Dv NULL ,
the calling process is not notified of I/O completion.
Pp
The order in which the requests are carried out is not specified,
and there is no guarantee that they will be executed sequentially.
Sh RETURN VALUES
If
Fa mode
is
Dv LIO_WAIT ,
the
Fn lio_listio
function returns 0 if the operations completed successfully,
otherwise \-1.
Pp
If
Fa mode
is
Dv LIO_NOWAIT ,
the
Fn lio_listio
function returns 0 if the operations are successfully queued,
otherwise \-1.
Sh ERRORS
The
Fn lio_listio
function will fail if:
Bl -tag -width Er
It Bq Er EAGAIN
There are not enough resources to enqueue the requests; or
the request would cause the system-wide limit
Dv AIO_MAX
to be exceeded.
It Bq Er EINTR
A signal interrupted the system call before it could be completed.
It Bq Er EINVAL
The
Fa mode
argument is neither
Dv LIO_WAIT
nor
Dv LIO_NOWAIT ,
or
Fa nent
is greater than
Dv AIO_LISTIO_MAX .
It Bq Er EIO
One or more requests failed.
El
Pp
In addition, the
Fn lio_listio
function may fail for any of the reasons listed for
Xr aio_read 3
and
Xr aio_write 3 .
Pp
If
Fn lio_listio
succeeds, or fails with an error code of
Er EAGAIN , EINTR ,
or
Er EIO ,
some of the requests may have been initiated.
The caller should check the error status of each
Vt aiocb
structure individually by calling
Xr aio_error 3 .
Sh SEE ALSO
Xr read 2 ,
Xr siginfo 2 ,
Xr write 2 ,
Xr aio 3 ,
Xr sigevent 3
Sh STANDARDS
The
Fn lio_listio
function is expected to conform to
St -p1003.1-2001 .