osfmk/man/device_read_inband.html

   1 <h2>device_read_inband</h2>
   2 <hr>
   3 <p>
   4 <strong>Function</strong> - Read a sequence of bytes "inband" from a device object.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>#include&ltdevice/device.h&gt</strong>
   8
   9 <strong>kern_return_t   device_read_inband</strong>
  10                 <strong>(mach_port_t</strong>                             <var>device</var>,
  11                  <strong>dev_mode_t</strong>                                <var>mode</var>,
  12                  <strong>recnum_t</strong>                                <var>recnum</var>,
  13                  <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var>,
  14                  <strong>io_buf_ptr_inband_t</strong>                       <var>data</var>,
  15                  <strong>mach_msg_type_number_t</strong>             <var>*data_count</var><strong>);</strong>
  16
  17
  18 <strong>#include&ltdevice/device_request.h&gt</strong>
  19
  20 <strong>kern_return_t   device_read_request_inband</strong>
  21                 <strong>(mach_port_t</strong>                             <var>device</var>,
  22                  <strong>mach_port_t</strong>                         <var>reply_port</var>,
  23                  <strong>dev_mode_t</strong>                                <var>mode</var>,
  24                  <strong>recnum_t</strong>                                <var>recnum</var>,
  25                  <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var><strong>);</strong>
  26
  27
  28 <strong>kern_return_t   ds_device_read_reply_inband</strong>
  29                 <strong>(mach_port_t</strong>                         <var>reply_port</var>,
  30                  <strong>kern_return_t</strong>                      <var>return_code</var>,
  31                  <strong>io_buf_ptr_inband_t</strong>                       <var>data</var>,
  32                  <strong>mach_msg_type_number_t</strong>              <var>data_count</var><strong>);</strong>
  33 </pre>
  34 <h3>PARAMETERS</h3>
  35 <dl>
  36 <p>
  37 <dt> <var>device</var>
  38 <dd>
  39 [in device send right]
  40 A device port to the device to be read.
  41 <p>
  42 <dt> <var>reply_port</var>
  43 <dd>
  44 [in reply receive (to be converted to send-once) right]
  45 The port to
  46 which the reply message is to be sent.
  47 <p>
  48 <dt> <var>mode</var>
  49 <dd>
  50 [in scalar]
  51 I/O mode value.  Meaningful options are:
  52 <dl>
  53 <p>
  54 <dt> <strong>D_NOWAIT</strong>
  55 <dd>
  56 Do not wait if data is unavailable.
  57 </dl>
  58 <p>
  59 <dt> <var>recnum</var>
  60 <dd>
  61 [in scalar]
  62 Record number to be read.
  63 <p>
  64 <dt> <var>bytes_wanted</var>
  65 <dd>
  66 [in scalar]
  67 Size of data transfer.
  68 <p>
  69 <dt> <var>return_code</var>
  70 <dd>
  71 [in scalar]
  72 The return status code from the read.
  73 <p>
  74 <dt> <var>data</var>
  75 <dd>
  76 [out array of bytes, in for asynchronous form]
  77 Returned data bytes.
  78 <p>
  79 <dt> <var>data_count</var>
  80 <dd>
  81 [out scalar, in for asynchronous form]
  82 Number of returned data bytes.
  83 </dl>
  84 <h3>DESCRIPTION</h3>
  85 <p>
  86 The <strong>device_read_inband</strong> function reads a sequence of bytes
  87 from a device object.  The
  88 meaning of <var>recnum</var> as well as the specific operation performed is device
  89 dependent.  This call differs from <strong>device_read</strong> in that
  90 the returned bytes are returned
  91 "inband" in the reply IPC message.
  92 <h3>RETURN VALUES</h3>
  93 <p>
  94 Only generic errors apply.
  95 <h3>RELATED INFORMATION</h3>
  96 <p>
  97 Functions:
  98 <a href="device_read.html"><strong>device_read</strong></a>,
  99 <a href="device_read_overwrite.html"><strong>device_read_overwrite</strong></a>,
 100 <a href="device_reply_server.html"><strong>device_reply_server</strong></a>.