projects / apple / xnu.git / blame
| Commit | Line | Data |
|---|---|---|
| 13fec989 A |
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: | |
| 50 | <a href="task_resume.html"><strong>task_resume</strong></a>, | |
| 51 | <a href="task_suspend.html"><strong>task_suspend</strong></a>, | |
| 52 | <a href="thread_abort.html"><strong>thread_abort</strong></a>, | |
| 53 | <a href="thread_get_state.html"><strong>thread_get_state</strong></a>, | |
| 54 | <a href="thread_info.html"><strong>thread_info</strong></a>, | |
| 55 | <a href="thread_resume.html"><strong>thread_resume</strong></a>, | |
| 56 | <a href="thread_set_state.html"><strong>thread_set_state</strong></a>, | |
| 57 | <a href="thread_terminate.html"><strong>thread_terminate</strong></a>. |