condition-variable Questions
1
Solved
I've looked into the VC++ implementation of std::condition_variable(lock,pred), basically, it looks like this:
template<class _Predicate>
void wait(unique_lock<mutex>& _Lck, _Pred...
Submultiple asked 26/2, 2017 at 16:2
2
Accoding to cppreference.com:
The thread that intends to modify the variable has to
acquire a std::mutex (typically via std::lock_guard)
perform the modification while the lock is he...
Associationism asked 26/1, 2017 at 5:7
2
Solved
For simplicity, let's assume that we have only one conditional variable to match a single condition that is reflected by a boolean.
1) Why does std::condition_variable::wait(...) locks the mutex a...
Impudence asked 20/1, 2017 at 18:13
2
I am trying to wait for a specific condition, and I would like advice as to how this is done best. I have a struct that looks like this (simplified):
type view struct {
timeFrameReached bool
Row...
Connote asked 19/1, 2017 at 21:2
3
Solved
I am using a std::condition_variable combined with a std::unique_lock like this.
std::mutex a_mutex;
std::condition_variable a_condition_variable;
std::unique_lock<std::mutex> a_lock(a_mutex...
Rancid asked 13/11, 2016 at 18:59
3
Solved
I am trying to understand what happens to a mutex when it is used in a condition variable.
In the following example, taken from cppreference
int main()
{
std::queue<int> produced_nums;
st...
Hosanna asked 22/10, 2012 at 20:33
1
Solved
In our Android app, we have UI component and core C++11 module. A thread is running based on std::chrono::system_clock::time_point, such as below:
while(this->m_ConditionVariable.wait_until(loc...
Sulfate asked 29/11, 2016 at 12:7
1
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This is a follow-up to Can C++11 condition_variables be used to synchronize processes?.
Can std::condition_variable objects be used as counting semaphores?
Methinks not because the object seems b...
Cento asked 31/10, 2016 at 2:3
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I'm trying to learn about C++11's std::condition_variable. I've read the articles at cppreference.com and cplusplus.com as well as C++0x has no semaphores? How to synchronize threads?.
My question...
Stickler asked 30/10, 2016 at 20:23
1
Solved
Consider the following simplistic example of condition variables:
bool pause = true;
boost::mutex::scoped_lock lock(m_mutex);
while (!pause) cv.wait(lock);
and
boost::mutex::scoped_lock lock(...
Barnwell asked 22/9, 2016 at 6:59
3
I am trying to use a thread within my class, then the thread needs to use a condition_variable, and the condition variable will be blocked until a predicate be changed to true. The code looks like ...
Ridotto asked 19/9, 2016 at 4:7
3
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As it turns out, condition_variable::wait_for should really be called condition_variable::wait_for_or_possibly_indefinitely_longer_than, because it needs to reacquire the lock before really timing ...
Trepang asked 8/8, 2014 at 1:7
4
Solved
When using timed_wait on a boost::condition_variable with a duration, will the wait condition time out after the duration even if the user (or ntp) changes the system time?
E.g.,
boost::posix_tim...
Teleplay asked 7/12, 2010 at 20:10
1
Solved
I am trying to add a condition_variable to handle threads, but get a compilation error at this line:
this->cv.wait(lk, []{return this->ready;});
Looks like the for the variable this->read...
Disjunctive asked 26/7, 2016 at 16:57
2
Solved
Assuming
no undefined behaviour occurs,
no deadlocks occur,
mutexes are locked and unlocked in the correct order by the correct threads the correct number of times,
non-recursive mutexes are not ...
Longer asked 13/5, 2016 at 8:51
2
Solved
I am not sure if I really understand why std::condition_variable needs a additional std::mutex as a parameter? Should it not be locking by its self?
#include <iostream>
#include <conditio...
Lymanlymann asked 12/5, 2016 at 7:50
3
If std::condition_variable can be signaled due to the spurious wakeups (and we can't be sure that the condition we need is really satisfied), why do C++ Standard Library provide the overloads of wa...
Salaried asked 26/1, 2016 at 11:30
3
Solved
I need to be clarified how lock and condition_variable work.
In the -slightly modified- code from here cplusplusreference
std::mutex m;
std::condition_variable cv;
std::string data;
bool ready = ...
Obmutescence asked 10/8, 2015 at 7:11
2
In the documentation for std::condition_variable, there is an overload of wait() taking as argument a predicate function. The function will wait until the first wake_up at which the predicate funct...
Dissipated asked 13/11, 2015 at 12:16
1
Solved
Consider the following example.
std::mutex mtx;
std::condition_variable cv;
void f()
{
{
std::unique_lock<std::mutex> lock( mtx );
cv.wait( lock ); // 1
}
std::cout << "f()\n";
}...
Wendel asked 6/10, 2015 at 19:25
1
Solved
I've tested this scenario in some environments, and I got the following flow:
However, from the man pages ( http://linux.die.net/man/3/pthread_cond_wait ) or ( http://linux.die.net/man/3/pthread...
Demagogy asked 10/9, 2015 at 10:43
4
Solved
I'm learning about C++11 concurrency, where my only prior experience with concurrency primitives was in Operating Systems class six years ago, so be gentle, if you can.
In C++11, we can write
std...
Lowson asked 15/6, 2012 at 0:8
2
We were working on our audio player project on mac and noticed that the power usage was so high (about 7x that of google chrome doing the same workload.)
I used xcode's energy profiling tool, one ...
Credent asked 27/3, 2015 at 20:58
1
Solved
I'm trying out Windows support for Condition Variables today (as provided by Microsoft for Windows Vista and later). To initialize a condition variable, I call InitializeConditionVariable(), which ...
Consecrate asked 10/3, 2015 at 23:27
1
Solved
my problem looks like this:
I've got a observer which holds a std::condition_variable and a std::mutex, my worker thread objects have a pointer to the observer. Each time a worker thread finished ...
Salenasalene asked 30/11, 2014 at 21:42
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