std::condition_variable::wait_until

 

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Threads Original: Threads The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
thread (C++11)
this_thread namespace Original: this_thread namespace The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
get_id (C++11) yield (C++11)	sleep_for (C++11) sleep_until (C++11)
Exclusão mútua Original: Mutual exclusion The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
mutex (C++11) timed_mutex (C++11)	recursive_mutex (C++11) recursive_timed_mutex (C++11)
Gestão de bloqueio genérico Original: Generic lock management The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
lock_guard (C++11) unique_lock (C++11) defer_lock_ttry_to_lock_tadopt_lock_t (C++11)(C++11)(C++11)	lock (C++11) try_lock (C++11) defer_locktry_to_lockadopt_lock (C++11)(C++11)(C++11)
Variáveis ​​de condição Original: Condition variables The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
condition_variable (C++11)
condition_variable_any (C++11)
notify_all_at_thread_exit (C++11)
cv_status (C++11)
Futuros Original: Futures The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
promise (C++11) future (C++11) shared_future (C++11) packaged_task (C++11) async (C++11)	launch (C++11) future_status (C++11) future_error (C++11) future_category (C++11) future_errc (C++11)

 

std::condition_variable

Funções de membro Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

condition_variable::condition_variable

condition_variable::~condition_variable

Notificação Original: Notification The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

condition_variable::notify_one

condition_variable::notify_all

Espera Original: Waiting The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

condition_variable::wait

condition_variable::wait_for

condition_variable::wait_until

Identificador nativo Original: Native handle The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

condition_variable::native handle

 

template<class Clock, class Duration > std::cv_status wait_until(std::unique_lock<std::mutex>& lock,                            conststd::chrono::time_point<Clock, Duration>& abs_time);	(1)	(desde C++11)
template<class Clock, class Duration, class Predicate > bool wait_until(std::unique_lock<mutex>& lock,                  conststd::chrono::time_point<Clock, Duration>& abs_time,                  Predicate pred);	(2)	(desde C++11)

wait_until faz com que o thread atual para bloquear até que a variável de condição é notificado, um tempo específico é alcançado, ou um despertar espúria ocorre, opcionalmente looping até que algum predicado é satisfeito.

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.

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1)

Atomicamente libera lock, bloqueia a thread atual em execução, e acrescenta-lo à lista de espera da thread em *this. A discussão será desbloqueado quando notify_all() ou notify_one() é executado, ou quando o abs_time ponto absoluto de tempo for atingido. Também pode ser desbloqueado spuriously. Quando desbloqueado, independentemente do motivo, lock é readquirido e sai wait_until. Se esta função saídas via de exceção, lock também é readquirida.

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.

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2)

Equivalente a

Original:

Equivalent to

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while(!pred())
    if(wait_until(lock, abs_time)==std::cv_status::timeout)
        return pred();
returntrue;

Essa sobrecarga pode ser usada para ignorar wakeups espúrios.

Original:

This overload may be used to ignore spurious wakeups.

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Parâmetros

lock	-	um objeto de tipo std :: unique_lock <std::mutex>, que deve ser bloqueado pelo thread atual Original: an object of type std::unique_lock<std::mutex>, which must be locked by the current thread The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
abs_time	-	um objecto do tipo std::chrono::time_point representando o momento em que parar de esperar 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 se o tempo de espera deve ser continuado 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:  bool pred();​

Valor de retorno

1)

std::cv_status::timeout se o tempo limite absoluto especificado por abs_time foi alcançado, 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.

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2)

false se o predicado pred ainda avalia a false após o tempo limite expirou abs_time, caso contrário true.

Original:

false if the predicate pred still evaluates to false after the abs_time timeout expired, otherwise true.

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Exceções

Pode lançar std::system_error, também podem propagar exceções lançadas por lock.lock() ou lock.unlock().

Original:

May throw std::system_error, may also propagate exceptions thrown by lock.lock() or lock.unlock().

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Notas

Chamar essa função se lock.mutex() não está bloqueada pelo atual segmento é um comportamento indefinido.

Original:

Calling this function if lock.mutex() is not locked by the current thread is undefined behavior.

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Chamar essa função se lock.mutex() não é o mesmo mutex como o utilizado por todos os outros segmentos que estão aguardando na variável mesma condição é um comportamento indefinido.

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.

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Exemplo

#include <iostream>#include <atomic>#include <condition_variable>#include <thread>#include <chrono>   std::condition_variable 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';elsestd::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();}

Potencial saída:

Thread 1 timed out. i == 0 Notifying... Thread 2 timed out. i == 0 Notifying again... Thread 3 finished waiting. i == 1

Veja também

wait	bloqueia o segmento atual até que a variável de condição é acordado 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. (função pública membro)
wait_for	Bloqueia o segmento atual até que a variável de condição é acordado ou após o período de tempo limite especificado 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. (função pública membro)