std::condition_variable_any::wait
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< cpp | thread | condition variable any
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template< class Lock > void wait( Lock& lock ); |
(1) | (desde C++11) |
template< class Lock, class Predicate > void wait( Lock& lock, Predicate pred ); |
(2) | (desde C++11) |
wait
faz com que o thread atual para bloquear até que a variável de condição é notificado ou um despertar espúria ocorre, opcionalmente looping até que algum predicado é satisfeito.Original:
wait
causes the current thread to block until the condition variable is notified 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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Atomicamente libera
2) 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. Também pode ser desbloqueado spuriously. Quando desbloqueado, independentemente do motivo, lock
é readquirido e sai wait
. 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. It may also be unblocked spuriously. When unblocked, regardless of the reason, lock
is reacquired and wait
exits. If this function exits via exception, lock
is also reacquired.The text has been machine-translated via Google Translate.
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Equivalente a
Original:
Equivalent to
The text has been machine-translated via Google Translate.
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while (!pred()) {
wait(lock);
}
Essa sobrecarga pode ser usada para ignorar despertares espúrias enquanto espera por uma condição específica a ser verdade.
Original:
This overload may be used to ignore spurious awakenings while waiting for a specific condition to become true.
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Índice |
[editar] Parâmetros
lock | - | um objeto de
Lock tipo que atenda aos requisitos BasicLockable , que devem ser bloqueadas pela thread atualOriginal: an object of type Lock that meets the BasicLockable requirements, 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. |
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(); |
[editar] Valor de retorno
(Nenhum)
Original:
(none)
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[editar] Exceções
Pode lançar std::system_error, também podem propagar exceções lançadas por lock.lock() ou lock.unlock().
Original:
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[editar] 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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[editar] Exemplo
#include <iostream> #include <condition_variable> #include <thread> #include <chrono> std::condition_variable_any cv; std::mutex cv_m; int i = 0; void waits() { std::unique_lock<std::mutex> lk(cv_m); std::cerr << "Waiting... \n"; cv.wait(lk, [](){return i == 1;}); std::cerr << "...finished waiting. i == 1\n"; } void signals() { std::this_thread::sleep_for(std::chrono::seconds(1)); std::cerr << "Notifying...\n"; cv.notify_all(); std::this_thread::sleep_for(std::chrono::seconds(1)); i = 1; std::cerr << "Notifying again...\n"; cv.notify_all(); } int main() { std::thread t1(waits), t2(waits), t3(waits), t4(signals); t1.join(); t2.join(); t3.join(); t4.join(); }
Saída:
Waiting... Waiting... Waiting... Notifying... Notifying again... ...finished waiting. i == 1 ...finished waiting. i == 1 ...finished waiting. i == 1
[editar] Veja também
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) | |
bloqueia o segmento atual até que a variável de condição é acordado ou até ponto de tempo especificado foi alcançado Original: blocks the current thread until the condition variable is woken up or until specified time point has been reached 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) |