1<h2>io_done_queue_wait</h2> 2<hr> 3<p> 4<strong>System Trap</strong> - Wait on an io_done_queue kernel object. 5<h3>SYNOPSIS</h3> 6<pre> 7<strong>kern_return_t io_done_queue_wait</strong> 8 <strong>(mach_port_t</strong> <var>queue</var>, 9 <strong>io_done_result_t</strong> <var>*result</var><strong>);</strong> 10</pre> 11<h3>PARAMETERS</h3> 12<dl> 13<p> 14<dt> <var>queue</var> 15<dd> 16[in io-done-queue send right] The port referencing the io_done_queue 17to be destroyed. 18<p> 19<dt> <var>result</var> 20<dd> 21[out structure] The data structure to be filled in with the completion 22status of the I/O operation. 23</dl> 24<h3>DESCRIPTION</h3> 25<p> 26The <strong>io_done_queue_wait</strong> interface is called to obtain the results of a 27previously requested asynchronous I/O operation. For each 28<strong>io_done_queue_wait</strong> invocation, the status of one I/O request is 29returned. If there are no pending I/O completions, io_done_queue_wait 30blocks in the kernel on the address of the completion queue. The 31mKernel, from interrupt context, enqueues (in FIFO order) completions 32(struct <strong>io_done_result</strong>'s) on the completion queue and posts a wakeup 33on the queue for each I/O completion. Completion processing previously 34done by the mKernel <strong>io_done thread</strong> is now done by the task thread when 35it awakens. 36<h3>RETURN VALUES</h3> 37<dl> 38 <dt> <strong>KERN_TERMINATED</strong> 39<dd> 40 Stale <strong>io_done_queue</strong> handle. 41 <p> 42 43 <dt> <strong>KERN_INVALID_ARGUMENT</strong> 44<dd> 45 Invalid <var>queue</var> parameter. 46 <p> 47<dt> <strong>KERN_INVALID_ARGUMENT</strong> 48<dd> 49 The <var>result</var> parameter is a bad address. 50 <p> 51</dl> 52<h3>RELATED INFORMATION</h3> 53<p> 54Functions: 55<a href="io_done_queue_create.html"><strong>io_done_queue_create</strong></a>, 56<a href="io_done_queue_wait.html"><strong>io_done_queue_wait</strong></a>, 57<a href="device_read_async.html"><strong>device_read_async</strong></a>, 58<a href="device_read_async_inband.html"><strong>device_read_async_inband</strong></a>, 59<a href="DR_overwrite_async.html"><strong>device_read_overwrite_async</strong></a>, 60<a href="device_write_async.html"><strong>device_write_async</strong></a>, 61<a href="device_write_async_inband.html"><strong>device_write_async_inband</strong></a>. 62