xref: /xnu-10002.81.5/osfmk/man/thread_suspend.html (revision 5e3eaea39dcf651e66cb99ba7d70e32cc4a99587)
1*5e3eaea3SApple OSS Distributions<h2>thread_suspend</h2>
2*5e3eaea3SApple OSS Distributions<hr>
3*5e3eaea3SApple OSS Distributions<p>
4*5e3eaea3SApple OSS Distributions<strong>Function</strong> - Suspend a thread.
5*5e3eaea3SApple OSS Distributions<h3>SYNOPSIS</h3>
6*5e3eaea3SApple OSS Distributions<pre>
7*5e3eaea3SApple OSS Distributions<strong>kern_return_t   thread_suspend</strong>
8*5e3eaea3SApple OSS Distributions                <strong>(thread_act_t</strong>                     <var>target_thread</var><strong>);</strong>
9*5e3eaea3SApple OSS Distributions</pre>
10*5e3eaea3SApple OSS Distributions<h3>PARAMETERS</h3>
11*5e3eaea3SApple OSS Distributions<dl>
12*5e3eaea3SApple OSS Distributions<p>
13*5e3eaea3SApple OSS Distributions<dt> <var>target_thread</var>
14*5e3eaea3SApple OSS Distributions<dd>
15*5e3eaea3SApple OSS Distributions[in thread send right]
16*5e3eaea3SApple OSS DistributionsThe thread to be suspended.
17*5e3eaea3SApple OSS Distributions</dl>
18*5e3eaea3SApple OSS Distributions<h3>DESCRIPTION</h3>
19*5e3eaea3SApple OSS Distributions<p>
20*5e3eaea3SApple OSS DistributionsThe <strong>thread_suspend</strong> function increments the suspend
21*5e3eaea3SApple OSS Distributionscount for <var>target_thread</var>
22*5e3eaea3SApple OSS Distributionsand prevents the thread from executing any more user-level instructions.
23*5e3eaea3SApple OSS Distributions<p>
24*5e3eaea3SApple OSS DistributionsIn this context, a user-level instruction can be either a machine instruction
25*5e3eaea3SApple OSS Distributionsexecuted in user mode or a system trap instruction, including
26*5e3eaea3SApple OSS Distributionsa page fault.  If a
27*5e3eaea3SApple OSS Distributionsthread is currently executing within a system trap, the kernel
28*5e3eaea3SApple OSS Distributionscode may continue
29*5e3eaea3SApple OSS Distributionsto execute until it reaches the system return code or it may
30*5e3eaea3SApple OSS Distributionssuspend within the
31*5e3eaea3SApple OSS Distributionskernel code.  In either case, the system trap returns when the thread resumes.
32*5e3eaea3SApple OSS Distributions<p>
33*5e3eaea3SApple OSS DistributionsTo resume a suspended thread, use <strong>thread_resume</strong>.  If
34*5e3eaea3SApple OSS Distributionsthe suspend count is
35*5e3eaea3SApple OSS Distributionsgreater than one, <strong>thread_resume</strong> must be repeated that
36*5e3eaea3SApple OSS Distributionsnumber of times.
37*5e3eaea3SApple OSS Distributions<h3>CAUTIONS</h3>
38*5e3eaea3SApple OSS Distributions<p>
39*5e3eaea3SApple OSS DistributionsUnpredictable results may occur if a program suspends a thread and alters its
40*5e3eaea3SApple OSS Distributionsuser state so that its direction is changed upon resuming.  Note that the
41*5e3eaea3SApple OSS Distributions<strong>thread_abort</strong> function allows a system call to be aborted
42*5e3eaea3SApple OSS Distributionsonly if it is progressing in a
43*5e3eaea3SApple OSS Distributionspredictable way.
44*5e3eaea3SApple OSS Distributions<h3>RETURN VALUES</h3>
45*5e3eaea3SApple OSS Distributions<p>
46*5e3eaea3SApple OSS DistributionsOnly generic errors apply.
47*5e3eaea3SApple OSS Distributions<h3>RELATED INFORMATION</h3>
48*5e3eaea3SApple OSS Distributions<p>
49*5e3eaea3SApple OSS DistributionsFunctions:
50*5e3eaea3SApple OSS Distributions<a href="task_resume.html"><strong>task_resume</strong></a>,
51*5e3eaea3SApple OSS Distributions<a href="task_suspend.html"><strong>task_suspend</strong></a>,
52*5e3eaea3SApple OSS Distributions<a href="thread_abort.html"><strong>thread_abort</strong></a>,
53*5e3eaea3SApple OSS Distributions<a href="thread_get_state.html"><strong>thread_get_state</strong></a>,
54*5e3eaea3SApple OSS Distributions<a href="thread_info.html"><strong>thread_info</strong></a>,
55*5e3eaea3SApple OSS Distributions<a href="thread_resume.html"><strong>thread_resume</strong></a>,
56*5e3eaea3SApple OSS Distributions<a href="thread_set_state.html"><strong>thread_set_state</strong></a>,
57*5e3eaea3SApple OSS Distributions<a href="thread_terminate.html"><strong>thread_terminate</strong></a>.
58