std::condition_variable_any::wait_until
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<tbody> </tbody> template< class Lock, class Clock, class Duration > std::cv_status wait_until( Lock& lock, const std::chrono::time_point<Clock, Duration>& abs_time); |
(1) | (seit C++11) |
template< class Lock, class Clock, class Duration, class Predicate > bool wait_until( Lock& lock, const std::chrono::time_point<Clock, Duration>& abs_time, Predicate pred); |
(2) | (seit C++11) |
wait_until bewirkt, dass der aktuelle Thread zu blockieren, bis die Bedingung variable mitgeteilt wird, eine bestimmte Zeit erreicht ist, oder eine falsche wakeup auftritt, wahlweise Schleife, bis einige Prädikat erfüllt ist .Original:
wait_until causes the current thread to block until the condition variable is notified, a specific time is reached, or a spurious wakeup occurs, optionally looping until some predicate is satisfied.The text has been machine-translated via Google Translate.
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1)
Atomar freigibt
lock, blockiert den aktuellen ausgeführten Threads, und fügt sie in die Liste der wartenden Threads auf *this. Der Faden wird entsperrt, wenn notify_all() oder notify_one() ausgeführt werden, oder wenn der absolute Zeitpunkt abs_time erreicht ist. Es kann auch fälschlicherweise entsperrt werden. Wenn freigegeben, egal aus welchem Grund, ist lock reacquired und wait_until beendet. Wenn diese Funktion tritt über Ausnahme ist lock auch zurückerworben .Original:
Atomically releases
lock, blocks the current executing thread, and adds it to the list of threads waiting on *this. The thread will be unblocked when notify_all() or notify_one() is executed, or when the absolute time point abs_time is reached. It may also be unblocked spuriously. When unblocked, regardless of the reason, lock is reacquired and wait_until exits. If this function exits via exception, lock is also reacquired.The text has been machine-translated via Google Translate.
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2)
Entspricht
Original:
Equivalent to
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while (!pred()) if (wait_until(lock, abs_time) == std::cv_status::timeout) return pred(); return true;
Diese Überlastung kann verwendet werden, um störende wakeups ignorieren .
Original:
This overload may be used to ignore spurious wakeups.
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Parameter
| lock | - | ein Objekt des Typs
Lock, die die Anforderungen BasicLockable, die durch den aktuellen Thread gesperrt werden müssen erfülltOriginal: an object of type Lock that meets the requirements of BasicLockable, which must be locked by the current threadThe text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| abs_time | - | ein Objekt vom Typ std::chrono::time_point repräsentiert die Zeit, wann man aufhören warten
Original: an object of type std::chrono::time_point representing the time when to stop waiting The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| pred | - | predicate which returns false wenn das Warten sollte fortgesetzt werden . Original: if the waiting should be continued The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. The signature of the predicate function should be equivalent to the following:
|
Rückgabewert
1)
std::cv_status::timeout wenn die absolute Timeout durch
abs_time angegeben wurde erreicht, std::cv_status::no_timeout overwise .Original:
std::cv_status::timeout if the absolute timeout specified by
abs_time was reached, std::cv_status::no_timeout overwise.The text has been machine-translated via Google Translate.
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2)
false wenn das Prädikat pred noch ausgewertet false nach dem abs_time Timeout abgelaufen, sonst true .Original:
false if the predicate pred still evaluates to false after the abs_time timeout expired, otherwise true.The text has been machine-translated via Google Translate.
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Ausnahmen
Kann std::system_error werfen, kann auch propagieren Ausnahmen
lock.lock() geworfen oder lock.unlock() .Original:
May throw std::system_error, may also propagate exceptions thrown by
lock.lock() or lock.unlock().The text has been machine-translated via Google Translate.
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Notes
Der Aufruf dieser Funktion, wenn
lock.mutex() nicht durch den aktuellen Thread gesperrt ist undefiniert .Original:
Calling this function if
lock.mutex() is not locked by the current thread is undefined behavior.The text has been machine-translated via Google Translate.
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Der Aufruf dieser Funktion, wenn
lock.mutex() nicht das gleiche Mutex als ein von allen anderen Threads, wartet derzeit auf der gleichen Bedingung variabel ist undefiniert verwendet .Original:
Calling this function if
lock.mutex() is not the same mutex as the one used by all other threads that are currently waiting on the same condition variable is undefined behavior.The text has been machine-translated via Google Translate.
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Beispiel
#include <iostream>
#include <atomic>
#include <condition_variable>
#include <thread>
#include <chrono>
std::condition_variable_any cv;
std::mutex cv_m;
std::atomic<int> i = ATOMIC_VAR_INIT(0);
void waits(int idx)
{
std::unique_lock<std::mutex> lk(cv_m);
auto now = std::chrono::system_clock::now();
if(cv.wait_until(lk, now + std::chrono::milliseconds(idx*100), [](){return i == 1;}))
std::cerr << "Thread " << idx << " finished waiting. i == " << i << '\n';
else
std::cerr << "Thread " << idx << " timed out. i == " << i << '\n';
}
void signals()
{
std::this_thread::sleep_for(std::chrono::milliseconds(120));
std::cerr << "Notifying...\n";
cv.notify_all();
std::this_thread::sleep_for(std::chrono::milliseconds(100));
i = 1;
std::cerr << "Notifying again...\n";
cv.notify_all();
}
int main()
{
std::thread t1(waits, 1), t2(waits, 2), t3(waits, 3), t4(signals);
t1.join();
t2.join();
t3.join();
t4.join();
}
Possible output:
Thread 1 timed out. i == 0
Notifying...
Thread 2 timed out. i == 0
Notifying again...
Thread 3 finished waiting. i == 1
Siehe auch
Blockiert den aktuellen Thread, bis die condition variable geweckt wird Original: blocks the current thread until the condition variable is woken up The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (öffentliche Elementfunktion) | |
Blockiert den aktuellen Thread, bis die condition variable geweckt wird oder die angegebenene Zeitspanne abgelaufen ist Original: blocks the current thread until the condition variable is woken up or after the specified timeout duration The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (öffentliche Elementfunktion) | |