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1 <h2>thread_suspend</h2>

2 <hr>

3 <p>

4 <strong>Function</strong> - Suspend a thread.

5 <h3>SYNOPSIS</h3>

6 <pre>

7 <strong>kern_return_t thread_suspend</strong>

8 <strong>(thread_act_t</strong> <var>target_thread</var><strong>);</strong>

9 </pre>

10 <h3>PARAMETERS</h3>

11 <dl>

12 <p>

13 <dt> <var>target_thread</var>

14 <dd>

15 [in thread send right]

16 The thread to be suspended.

17 </dl>

18 <h3>DESCRIPTION</h3>

19 <p>

20 The <strong>thread_suspend</strong> function increments the suspend

21 count for <var>target_thread</var>

22 and prevents the thread from executing any more user-level instructions.

23 <p>

24 In this context, a user-level instruction can be either a machine instruction

25 executed in user mode or a system trap instruction, including

26 a page fault. If a

27 thread is currently executing within a system trap, the kernel

28 code may continue

29 to execute until it reaches the system return code or it may

30 suspend within the

31 kernel code. In either case, the system trap returns when the thread resumes.

32 <p>

33 To resume a suspended thread, use <strong>thread_resume</strong>. If

34 the suspend count is

35 greater than one, <strong>thread_resume</strong> must be repeated that

36 number of times.

37 <h3>CAUTIONS</h3>

38 <p>

39 Unpredictable results may occur if a program suspends a thread and alters its

40 user state so that its direction is changed upon resuming. Note that the

41 <strong>thread_abort</strong> function allows a system call to be aborted

42 only if it is progressing in a

43 predictable way.

44 <h3>RETURN VALUES</h3>

45 <p>

46 Only generic errors apply.

47 <h3>RELATED INFORMATION</h3>

48 <p>

49 Functions:

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

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

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

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

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

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

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

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