1<h2>thread_sample</h2>
2<hr>
3<p>
4<strong>Function</strong> - Perform periodic PC sampling for a thread.
5<h3>SYNOPSIS</h3>
6<pre>
7<strong>kern_return_t   thread_sample</strong>
8                <strong>(thread_act_t</strong>                     <var>sample_thread</var>,
9                 <strong>mach_port_make_send_t</strong>               <var>reply_port</var><strong>);</strong>
10</pre>
11<h3>PARAMETERS</h3>
12<dl>
13<p>
14<dt> <var>sample_thread</var> 
15<dd>
16[in thread send right]
17Thread whose PC is to be sampled
18<p>
19<dt> <var>reply_port</var> 
20<dd>
21[in sample receive (to be converted to send) right]
22Port to which PC 
23sample buffers are sent.  A value of <strong>MACH_PORT_NULL</strong> stops PC 
24sampling for the thread.
25</dl>
26<h3>DESCRIPTION</h3>
27<p>
28The <strong>thread_sample</strong> function causes the program counter
29(PC) of the specified 
30<var>sample_thread</var> to be sampled periodically (whenever the thread happens to be 
31running at the time of the kernel's "hardclock" interrupt). 
32The set of PC sample 
33values obtained are saved in buffers which are sent to the specified
34<var>reply_port</var> in 
35<strong>receive_samples</strong> messages.
36<h3>RETURN VALUES</h3>
37<p>
38Only generic errors apply.
39<h3>RELATED INFORMATION</h3>
40<p>
41Functions:
42<a href="task_sample.html"><strong>task_sample</strong></a>,
43<a href="receive_samples.html"><strong>receive_samples</strong></a>.
44