[apple/xnu.git] / osfmk / man / device_read_inband.html

<h2>device_read_inband</h2>\r<hr>\r<p>\r<strong>Function</strong> - Read a sequence of bytes "inband" from a device object.\r<h3>SYNOPSIS</h3>\r<pre>\r<strong>#include&ltdevice/device.h&gt</strong>\r\r<strong>kern_return_t   device_read_inband</strong>\r                <strong>(mach_port_t</strong>                             <var>device</var>,\r                 <strong>dev_mode_t</strong>                                <var>mode</var>,\r                 <strong>recnum_t</strong>                                <var>recnum</var>,\r                 <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var>,\r                 <strong>io_buf_ptr_inband_t</strong>                       <var>data</var>,\r                 <strong>mach_msg_type_number_t</strong>             <var>*data_count</var><strong>);</strong>\r\r\r<strong>#include&ltdevice/device_request.h&gt</strong>\r\r<strong>kern_return_t   device_read_request_inband</strong>\r                <strong>(mach_port_t</strong>                             <var>device</var>,\r                 <strong>mach_port_t</strong>                         <var>reply_port</var>,\r                 <strong>dev_mode_t</strong>                                <var>mode</var>,\r                 <strong>recnum_t</strong>                                <var>recnum</var>,\r                 <strong>io_buf_len_t</strong>                      <var>bytes_wanted</var><strong>);</strong>\r\r\r<strong>kern_return_t   ds_device_read_reply_inband</strong>\r                <strong>(mach_port_t</strong>                         <var>reply_port</var>,\r                 <strong>kern_return_t</strong>                      <var>return_code</var>,\r                 <strong>io_buf_ptr_inband_t</strong>                       <var>data</var>,\r                 <strong>mach_msg_type_number_t</strong>              <var>data_count</var><strong>);</strong>\r</pre>\r<h3>PARAMETERS</h3>\r<dl>\r<p>\r<dt> <var>device</var> \r<dd>\r[in device send right]\rA device port to the device to be read.\r<p>\r<dt> <var>reply_port</var> \r<dd>\r[in reply receive (to be converted to send-once) right]\rThe port to \rwhich the reply message is to be sent.\r<p>\r<dt> <var>mode</var> \r<dd>\r[in scalar]\rI/O mode value.  Meaningful options are:\r<dl>\r<p>\r<dt> <strong>D_NOWAIT</strong>\r<dd>\rDo not wait if data is unavailable.\r</dl>\r<p>\r<dt> <var>recnum</var> \r<dd>\r[in scalar]\rRecord number to be read.\r<p>\r<dt> <var>bytes_wanted</var> \r<dd>\r[in scalar]\rSize of data transfer.\r<p>\r<dt> <var>return_code</var> \r<dd>\r[in scalar]\rThe return status code from the read.\r<p>\r<dt> <var>data</var> \r<dd>\r[out array of bytes, in for asynchronous form]\rReturned data bytes.\r<p>\r<dt> <var>data_count</var> \r<dd>\r[out scalar, in for asynchronous form]\rNumber of returned data bytes.\r</dl>\r<h3>DESCRIPTION</h3>\r<p>\rThe <strong>device_read_inband</strong> function reads a sequence of bytes\rfrom a device object.  The \rmeaning of <var>recnum</var> as well as the specific operation performed is device\rdependent.  This call differs from <strong>device_read</strong> in that\rthe returned bytes are returned \r"inband" in the reply IPC message.\r<h3>RETURN VALUES</h3>\r<p>\rOnly generic errors apply.\r<h3>RELATED INFORMATION</h3>\r<p>\rFunctions:\r<a href="device_read.html"><strong>device_read</strong></a>,\r<a href="device_read_overwrite.html"><strong>device_read_overwrite</strong></a>,\r<a href="device_reply_server.html"><strong>device_reply_server</strong></a>.\r