1 '\" te
   2 .\"  Copyright (c) 2008, Sun Microsystems, Inc.  All Rights Reserved.
   3 .\" Copyright 1989 AT&T
   4 .\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
   5 .\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
   6 .\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
   7 .TH AWRITE 9E "Mar 28, 1997"
   8 .SH NAME
   9 awrite \- asynchronous write to a device
  10 .SH SYNOPSIS
  11 .LP
  12 .nf
  13 #include <sys/uio.h>
  14 #include <sys/aio_req.h>
  15 #include <sys/cred.h>
  16 #include <sys/ddi.h>
  17 #include <sys/sunddi.h>
  18 
  19 \fBintprefix\fR\fBawrite\fR(\fBdev_t\fR \fIdev\fR, \fBstruct aio_req *\fR\fIaio_reqp\fR,
  20      \fBcred_t *\fR\fIcred_p\fR);
  21 .fi
  22 
  23 .SH INTERFACE LEVEL
  24 .sp
  25 .LP
  26 Solaris \fBDDI \fRspecific (Solaris DDI). This entry point is optional. Drivers
  27 that do not support an  \fBawrite()\fR entry point should use  \fBnodev\fR(9F)
  28 .SH PARAMETERS
  29 .sp
  30 .ne 2
  31 .na
  32 \fB\fIdev\fR\fR
  33 .ad
  34 .RS 12n
  35 Device number.
  36 .RE
  37 
  38 .sp
  39 .ne 2
  40 .na
  41 \fB\fIaio_reqp\fR\fR
  42 .ad
  43 .RS 12n
  44 Pointer to the  \fBaio_req\fR(9S) structure that describes where the data is
  45 stored.
  46 .RE
  47 
  48 .sp
  49 .ne 2
  50 .na
  51 \fB\fIcred_p\fR\fR
  52 .ad
  53 .RS 12n
  54 Pointer to the  credential structure.
  55 .RE
  56 
  57 .SH DESCRIPTION
  58 .sp
  59 .LP
  60 The driver's \fBawrite()\fR routine is called to perform an asynchronous write.
  61 \fBgetminor\fR(9F) can be used to  access the minor number component of the
  62 \fIdev\fR argument. \fBawrite()\fR may use the  credential structure pointed to
  63 by  \fIcred_p\fR to check for superuser access by calling  \fBdrv_priv\fR(9F).
  64 The  \fBawrite()\fR routine may also examine the  \fBuio\fR(9S) structure
  65 through the  \fBaio_req\fR structure pointer,  \fBaio_reqp\fR. \fBawrite()\fR
  66 must call \fBaphysio\fR(9F) with the \fBaio_req\fR pointer and a pointer to the
  67 driver's \fBstrategy\fR(9E) routine.
  68 .sp
  69 .LP
  70 No fields of the \fBuio\fR(9S) structure pointed to by \fBaio_req\fR, other
  71 than \fBuio_offset\fR or \fBuio_loffset\fR, may be modified for non-seekable
  72 devices.
  73 .SH RETURN VALUES
  74 .sp
  75 .LP
  76 The  \fBawrite()\fR routine should return   \fB0\fR for success, or the
  77 appropriate error number.
  78 .SH CONTEXT
  79 .sp
  80 .LP
  81 This function is called from user context only.
  82 .SH EXAMPLES
  83 .LP
  84 \fBExample 1 \fRUsing the \fBawrite()\fR routine:
  85 .sp
  86 .LP
  87 The following is an example of an  \fBawrite()\fR routine:
  88 
  89 .sp
  90 .in +2
  91 .nf
  92 static int
  93 xxawrite(dev_t dev, struct aio_req *aio, cred_t *cred_p)
  94 {
  95         int instance;
  96         struct xxstate *xsp;
  97 
  98         instance = getminor(dev);
  99         xsp = ddi_get_soft_state(statep, instance);
 100         /*Verify soft state structure has been allocated */
 101         if (xsp == NULL)
 102                  return (ENXIO);
 103         return (aphysio(xxstrategy, anocancel, dev, B_WRITE, \e
 104         xxminphys, aio));
 105 }
 106 .fi
 107 .in -2
 108 
 109 .SH SEE ALSO
 110 .sp
 111 .LP
 112 \fBwrite\fR(2), \fBaiowrite\fR(3C), \fBaread\fR(9E), \fBread\fR(9E),
 113 \fBstrategy\fR(9E), \fBwrite\fR(9E), \fBanocancel\fR(9F), \fBaphysio\fR(9F),
 114 \fBddi_get_soft_state\fR(9F), \fBdrv_priv\fR(9F), \fBgetminor\fR(9F),
 115 \fBminphys\fR(9F), \fBnodev\fR(9F), \fBaio_req\fR(9S), \fBcb_ops\fR(9S),
 116 \fBuio\fR(9S)
 117 .sp
 118 .LP
 119 \fIWriting Device Drivers\fR
 120 .SH BUGS
 121 .sp
 122 .LP
 123 There is no way other than calling \fBaphysio\fR(9F) to accomplish an
 124 asynchronous write.