<h2>device_write</h2>

<strong>Function</strong> - Write a sequence of bytes to a specific device.

<h3>SYNOPSIS</h3>

<strong>#include&ltdevice/device.h&gt</strong>

<strong>kern_return_t device_write</strong>

<strong>(device_t</strong> <var>device</var>,

<strong>mach_port_t</strong> <var>reply_port</var>,

<strong>dev_mode_t</strong> <var>mode</var>,

<strong>recnum_t</strong> <var>recnum</var>,

<strong>io_buf_ptr_t</strong> <var>data</var>,

<strong>mach_msg_type_number_t</strong> <var>data_count</var>,

<strong>io_buf_len_t</strong> <var>io_buf_len_t</var><strong>);</strong>

<strong>#include&ltdevice/device_request.h&gt</strong>

<strong>kern_return_t device_write_request</strong>

<strong>(mach_port_t</strong> <var>device</var>,

<strong>mach_port_t</strong> <var>reply_port</var>,

<strong>dev_mode_t</strong> <var>mode</var>,

<strong>recnum_t</strong> <var>recnum</var>,

<strong>io_buf_ptr_t</strong> <var>data</var>,

<strong>mach_msg_type_number_t</strong> <var>data_count</var><strong>);</strong>

<strong>kern_return_t ds_device_write_reply</strong>

<strong>(mach_port_t</strong> <var>reply_port</var>,

<strong>kern_return_t</strong> <var>return_code</var>,

<strong>io_buf_len_t</strong> <var>bytes_written</var><strong>);</strong>

<h3>PARAMETERS</h3>

<dt> <var>device</var>

[in device send right]

A device port to the device to be written.

<dt> <var>reply_port</var>

[in reply receive (to be converted to send-once) right]

The port to

which the reply message is to be sent.

<dt> <var>mode</var>

[in scalar]

I/O mode value. Meaningful options are:

<dt> <strong>D_NOWAIT</strong>

Do not wait for I/O completion.

<dt> <var>recnum</var>

[in scalar]

Record number to be written.

<dt> <var>data</var>

[pointer to in array of bytes]

Data bytes to be written.

<dt> <var>data_count</var>

[in scalar]

Number of data bytes to be written.

<dt> <var>return_code</var>

[in scalar]

The return status code from the write.

<dt> <var>bytes_written</var>

[out scalar, in for asynchronous form]

Size of data transfer.

<h3>DESCRIPTION</h3>

The <strong>device_write</strong> function writes a sequence of bytes

to a device object. The

meaning of <var>recnum</var> as well as the specific operation performed is device

dependent.

<h3>RETURN VALUES</h3>

Only generic errors apply.

<h3>RELATED INFORMATION</h3>

Functions:

<a href="device_write_inband.html"><strong>device_write_inband</strong></a>,

<a href="device_reply_server.html"><strong>device_reply_server</strong></a>.