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43 .Fn msleep "void *chan" "struct mtx *mtx" "int priority" "const char *wmesg" "int timo"
45 .Fn msleep_spin "void *chan" "struct mtx *mtx" "const char *wmesg" "int timo"
47 .Fn pause "const char *wmesg" "int timo"
49 .Fn tsleep "void *chan" "int priority" "const char *wmesg" "int timo"
51 .Fn wakeup "void *chan"
53 .Fn wakeup_one "void *chan"
63 handle event-based thread blocking.
64 If a thread must wait for an
65 external event, it is put to sleep by
71 Threads may also wait using one of the locking primitive sleep routines
79 is an arbitrary address that uniquely identifies the event on which
80 the thread is being put to sleep.
81 All threads sleeping on a single
85 often called from inside an interrupt routine, to indicate that the
86 resource the thread was blocking on is available now.
90 specifies a new priority for the thread as well as some optional flags.
91 If the new priority is not 0,
92 then the thread will be made
93 runnable with the specified
100 flag, signals are checked before and after sleeping, otherwise signals are
104 is set and a signal needs to be delivered,
106 is returned if the current system call should be restarted if
109 is returned if the system call should be interrupted by the signal
115 is a string describing the sleep condition for tools like
117 Due to the limited space of those programs to display arbitrary strings,
118 this message should not be longer than 6 characters.
122 specifies a timeout for the sleep.
126 then the thread will sleep for at most
129 If the timeout expires,
130 then the sleep function will return
133 Several of the sleep functions including
136 and the locking primitive sleep routines specify an additional lock
138 The lock will be released before sleeping and reacquired
139 before the sleep routine returns.
145 the lock will not be reacquired before returning.
146 The lock is used to ensure that a condition can be checked atomically,
147 and that the current thread can be suspended without missing a
148 change to the condition, or an associated wakeup.
149 In addition, all of the sleep routines will fully drop the
153 while the thread is suspended and will reacquire the
155 mutex before the function returns.
158 mutex may be specified as the lock to drop.
159 In that case, however, the
163 To avoid lost wakeups,
164 either a lock should be used to protect against races,
165 or a timeout should be specified to place an upper bound on the delay due
170 function should only be invoked with a timeout of 0 when the
176 function requires that
178 reference a default, i.e. non-spin, mutex.
179 Its use is deprecated in favor of
181 which provides identical behavior.
185 function requires that
187 reference a spin mutex.
190 function does not accept a
192 parameter and thus does not support changing the current thread's priority,
196 or catching signals via the
202 function is a wrapper around
204 that suspends execution of the current thread for the indicated timeout.
205 The thread can not be awakened early by signals or calls to
212 function makes the first thread in the queue that is sleeping on the
216 This reduces the load when a large number of threads are sleeping on
217 the same address, but only one of them can actually do any useful work
220 Due to the way it works, the
222 function requires that only related threads sleep on a specific
225 It is the programmer's responsibility to choose a unique
230 function did not require this, though it was never good practice
231 for threads to share a
238 pay particular attention to ensure that no other threads wait on the
242 If the thread is awakened by a call to
250 and locking primitive sleep functions return 0.
251 Otherwise, a non-zero error code is returned.
256 and the locking primitive sleep functions will fail if:
261 flag was specified, a signal was caught, and the system call should be
266 flag was specified, a signal was caught, and the system call should be
268 .It Bq Er EWOULDBLOCK
269 A non-zero timeout was specified and the timeout expired.
286 They were probably also present in the preceding
289 They were the basic process synchronization model.
295 and added the parameters
301 function was removed in
321 This manual page was written by
322 .An J\(:org Wunsch Aq joerg@FreeBSD.org .