2 .\" Copyright (c) 1996 Joerg Wunsch
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48 .Fn msleep "void *chan" "struct mtx *mtx" "int priority" "const char *wmesg" "int timo"
50 .Fn msleep_sbt "void *chan" "struct mtx *mtx" "int priority" \
51 "const char *wmesg" "sbintime_t sbt" "sbintime_t pr" "int flags"
53 .Fn msleep_spin "void *chan" "struct mtx *mtx" "const char *wmesg" "int timo"
55 .Fn msleep_spin_sbt "void *chan" "struct mtx *mtx" "const char *wmesg" \
56 "sbintime_t sbt" "sbintime_t pr" "int flags"
58 .Fn pause "const char *wmesg" "int timo"
60 .Fn pause_sig "const char *wmesg" "int timo"
62 .Fn pause_sbt "const char *wmesg" "sbintime_t sbt" "sbintime_t pr" \
65 .Fn tsleep "void *chan" "int priority" "const char *wmesg" "int timo"
67 .Fn tsleep_sbt "void *chan" "int priority" "const char *wmesg" \
68 "sbintime_t sbt" "sbintime_t pr" "int flags"
70 .Fn wakeup "void *chan"
72 .Fn wakeup_one "void *chan"
84 handle event-based thread blocking.
85 If a thread must wait for an
86 external event, it is put to sleep by
94 Threads may also wait using one of the locking primitive sleep routines
102 is an arbitrary address that uniquely identifies the event on which
103 the thread is being put to sleep.
104 All threads sleeping on a single
106 are woken up later by
108 often called from inside an interrupt routine, to indicate that the
109 resource the thread was blocking on is available now.
113 specifies a new priority for the thread as well as some optional flags.
114 If the new priority is not 0,
115 then the thread will be made
116 runnable with the specified
120 should never be used, as it is for compatibility only.
121 A new priority of 0 means to use the thread's current priority when
122 it is made runnable again.
128 flag, pending signals are allowed to interrupt the sleep, otherwise
129 pending signals are ignored during the sleep.
132 is set and a signal becomes pending,
134 is returned if the current system call should be restarted if
137 is returned if the system call should be interrupted by the signal
143 is a string describing the sleep condition for tools like
145 Due to the limited space of those programs to display arbitrary strings,
146 this message should not be longer than 6 characters.
150 specifies a timeout for the sleep.
154 then the thread will sleep for at most
157 If the timeout expires,
158 then the sleep function will return
162 .Fn msleep_spin_sbt ,
170 It allows the caller to specify relative or absolute wakeup time with higher resolution
175 allows the caller to specify wanted absolute event precision.
178 allows the caller to pass additional
179 .Fn callout_reset_sbt
182 Several of the sleep functions including
185 and the locking primitive sleep routines specify an additional lock
187 The lock will be released before sleeping and reacquired
188 before the sleep routine returns.
194 the lock will not be reacquired before returning.
195 The lock is used to ensure that a condition can be checked atomically,
196 and that the current thread can be suspended without missing a
197 change to the condition, or an associated wakeup.
198 In addition, all of the sleep routines will fully drop the
202 while the thread is suspended and will reacquire the
204 mutex before the function returns.
207 mutex may be specified as the lock to drop.
208 In that case, however, the
212 To avoid lost wakeups,
213 either a lock should be used to protect against races,
214 or a timeout should be specified to place an upper bound on the delay due
219 function should only be invoked with a timeout of 0 when the
225 function requires that
227 reference a default, i.e. non-spin, mutex.
228 Its use is deprecated in favor of
230 which provides identical behavior.
234 function requires that
236 reference a spin mutex.
239 function does not accept a
241 parameter and thus does not support changing the current thread's priority,
245 or catching signals via the
251 function is a wrapper around
253 that suspends execution of the current thread for the indicated timeout.
254 The thread can not be awakened early by signals or calls to
260 function is a variant of
262 which can be awakened early by signals.
266 function makes the first thread in the queue that is sleeping on the
270 This reduces the load when a large number of threads are sleeping on
271 the same address, but only one of them can actually do any useful work
274 Due to the way it works, the
276 function requires that only related threads sleep on a specific
279 It is the programmer's responsibility to choose a unique
284 function did not require this, though it was never good practice
285 for threads to share a
292 pay particular attention to ensure that no other threads wait on the
296 If the timeout given by
300 is based on an absolute real-time clock value,
301 then the thread should copy the global
305 member before reading the RTC.
306 If the real-time clock is adjusted, these functions will set
308 to zero and return zero.
309 The caller should reconsider its orientation with the new RTC value.
311 When awakened by a call to
315 if a signal is pending and
318 a non-zero error code is returned.
319 If the thread is awakened by a call to
327 and locking primitive sleep functions return 0.
328 Zero can also be returned when the real-time clock is adjusted;
331 Otherwise, a non-zero error code is returned.
336 and the locking primitive sleep functions will fail if:
341 flag was specified, a signal was caught, and the system call should be
346 flag was specified, a signal was caught, and the system call should be
348 .It Bq Er EWOULDBLOCK
349 A non-zero timeout was specified and the timeout expired.
367 They were probably also present in the preceding
370 They were the basic process synchronization model.
376 and added the parameters
382 function was removed in
406 This manual page was written by
407 .An J\(:org Wunsch Aq Mt joerg@FreeBSD.org .