condition-variable Questions
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Some kernels provide a "flush" operation on semaphore to unblock all tasks waiting on a semaphore.
For example, VxWorks has a semFlush() API that atomically unblocks all tasks pended on a specifie...
Helvellyn asked 2/3, 2020 at 22:20
1
An example from The Linux Programming Interface:
In the producer threads, we would have code such as the following:
static pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;
static int avail = 0...
Swashbuckler asked 25/12, 2019 at 14:4
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It's written in POSIX threads tutorial
https://computing.llnl.gov/tutorials/pthreads/
that it is a logical error.
my question is why it is a logical error?
In my program i need to use these signa...
Kevin asked 4/4, 2011 at 9:35
3
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For example the C++11 interfaces
I am having a hard time figuring out when to use which of these things (cv, mutex and lock).
Can anyone please explain or point to a resource?
Thanks in advance.
Dysprosium asked 28/6, 2009 at 18:7
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I am currently studying Google's Filament job system. You can find the source code here. The part that confuses me is this requestExit() method:
void JobSystem::requestExit() noexcept {
mExitRequ...
Concavity asked 10/6, 2019 at 4:52
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My question is does std::promise notify the associated std::future through using a std::condition_variable?
I search the source code of std::promise and found this website. But I didn't see std::...
Britzka asked 7/6, 2019 at 7:44
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I am trying to understand the difference between spurious vs lost wakeup in case of a condition variable. Following is small piece code I tried. I understand that 'consumer' in this case could wake...
Shoot asked 30/5, 2019 at 19:55
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I’m reading up on pthread.h; the condition variable related functions (like pthread_cond_wait(3)) require a mutex as an argument. Why? As far as I can tell, I’m going to be creating a mutex just to...
Smalley asked 4/5, 2010 at 8:5
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I am using code that runs on ARM (not Intel processor). Running c++11 code example (CODE A) from: http://www.cplusplus.com/reference/condition_variable/condition_variable/wait_for/ to test the wait...
Interradial asked 23/1, 2019 at 8:47
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I am using C++11 and I have a std::thread which is a class member, and it sends information to listeners every 2 minutes. Other that that it just sleeps. So, I have made it sleep for 2 minutes, the...
Basrelief asked 2/10, 2018 at 14:43
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I have yet to find a clear explanation of the differences between Condition and Event classes in the threading module. Is there a clear use case where one would be more helpful than the other? All ...
Mythopoeia asked 15/9, 2011 at 0:29
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Among the options below, is there any correct way to deal with spurious wakeups when using conditional variables?
1) Put the wait(unique_lock_ul) into an infinite while loop, using a boolean
uni...
Bashee asked 5/9, 2018 at 19:29
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I'm trying to implement some cross-platform code in C++11. Part of this code implements a semaphore object using a std::condition_variable. When I need to do a timed wait on the semaphore, I use wa...
Marsha asked 23/6, 2018 at 21:42
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Consider the following codesnippet:
#include <iostream>
#include <condition_variable>
#include <chrono>
#include <mutex>
int main () {
std::mutex y;
std::condition_varia...
Copenhaver asked 15/8, 2018 at 12:49
2
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I tried including std::condition_variable as a class member, and got a lot of compilation errors when passing an object of this class to a std::thread. I cut down all the other code from my actual ...
Kathikathiawar asked 28/6, 2018 at 16:49
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I'm working on an application where I currently have only one condition variable and lots of wait statements with different conditions. Whenever one of the queues or some other state is changed I j...
Logical asked 29/5, 2018 at 9:18
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I'm trying to implement an multi-thread job, a producer and a consumer, and basically what I want to do is, when consumer finishes the data, it notifies the producer so that producer provides new d...
Kasey asked 7/5, 2018 at 14:17
0
In the chapter 6 of C++ Concurrency in Action, it implements a thread-safe queue. Here is the complete code. But I find there may be something wrong with its use of condition variable.
std::uniqu...
Dacoity asked 6/5, 2018 at 3:19
4
I have the following code, which deadlocks on the commented lines. Basically f1 and f2 run as individual threads in the program. f1 expects i to be 1 and decrements it, notifying the cv. f2 expects...
Pigeontoed asked 3/4, 2018 at 5:17
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As it is said that Mutex are needed to protect the Condition Variables.
Is the reference here to the actual condition variable declared as pthread_cond_t
OR
A normal shared variable count whose va...
Malonylurea asked 18/5, 2012 at 7:8
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The reference I'm using explains the two in the following way:
wait_for "blocks the current thread until the condition variable is woken up or after the specified timeout duration"
wait_until "bl...
Longshoreman asked 30/10, 2012 at 15:25
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First a little context: I'm in the process of learning about threading in C++11 and for this purpose, I'm trying to build a small actor class, essentially (I left the exception handling and propaga...
Cordova asked 7/12, 2014 at 8:40
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I stumbled over the following code in Bjarne Stroustrup's "The C++ Programming Language, 4th Edition" on page 119:
queue<Message> mqueue;
condition_variable mcond;
mutex mmutex;
void consum...
Compilation asked 31/7, 2017 at 12:23
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I'm confused about conditions_variables and how to use them (safely). In my application I've a class that makes a gui-thread but while the gui is constructed by the gui-thread, the main thread need...
Achitophel asked 10/5, 2017 at 16:30
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I'm trying to launch new threads as soon as work in previous worker_thread has started, but maybe ended or not. I've replaced started and ended work with time delays. My code is:
#include <iost...
Sthenic asked 1/4, 2017 at 12:32
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