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Boost - performing periodic tasks using boost::thread

Boost, threads, chrono

I propose to write a small console program that will perform one task at regular intervals.

For example, the program starts and makes 10 samples within 10 seconds, while the program will display information about the number of the countdown in the console.

The program will work as follows.

Project structure

The project uses the CMake build system, so the project structure will be as follows..

CMakeLists.txt

Here is the standard CMake config for building the project.

cmake_minimum_required (VERSION 3.8)

project(Periodic)

set(CMAKE_CXX_STANDARD 17)
set(Boost_USE_STATIC_LIBS ON)

find_package(Boost 1.68 REQUIRED COMPONENTS thread)

set(SOURCE_FILES
        Periodic/main.cpp
        Periodic/PeriodicTask.cpp)

SET(HEADER_FILES
        Periodic/PeriodicTask.h)

if(Boost_FOUND)
    include_directories(${Boost_INCLUDE_DIRS})
    add_executable(Periodic ${SOURCE_FILES} ${HEADER_FILES})
    target_link_libraries(Periodic ${Boost_LIBRARIES})
endif()

PeriodicTask.h

Header file of the periodic task.

In the simplest case, to create a class of a periodic problem, we need:

  • a trigger period
  • object std::function to store the task
  • variable bool to stop and start the task. In this example, we will not stop the task, but if we add run / stop methods, then it is quite possible to implement it.
  • boost::thread - a thread without which this functionality cannot be implemented
#pragma once

#include <boost/thread.hpp>
#include <boost/chrono.hpp>
#include <functional>
#include <atomic>

class PeriodicTask
{
public:
    explicit PeriodicTask(const boost::chrono::milliseconds &period, const std::function<void()> &func);

    virtual ~PeriodicTask();

private:
    boost::chrono::milliseconds m_period;   // Task period
    std::function<void()> m_func;           // The function that will perform the periodic task
    std::atomic<bool> m_running;            // A variable that indicates that the task is running, with the help of it you can stop the task in the future
    boost::thread m_thread;                 // Task thread
};

PeriodicTask.cpp

#include "PeriodicTask.h"

PeriodicTask::PeriodicTask(const boost::chrono::milliseconds &period, const std::function<void()> &func) :
    m_period(period),
    m_func(func),
    m_running(true)
{
    // Create a stream object to perform a periodic task.
    m_thread = boost::thread([this]
    {
        while (m_running)
        {
            // To perform a task with a specific period, immerse the stream in a dream after each task execution.
            boost::this_thread::sleep_for(m_period);
            if (m_running)
            {
                // perform the task
                m_func();
            }
        }
    });
}

PeriodicTask::~PeriodicTask()
{
    // When destroying an object with a periodic task
    m_running = false;
    // interrupt the flow, otherwise the program will not release system resources until the flow comes out of sleep
    // this is critical if the trigger period of the task is measured in tens of seconds and more
    m_thread.interrupt();
    m_thread.join();
}

main.cpp

File with main function. When we create an object of a periodic task, we put the lambda function in it as the task, as the easiest way to indicate what work needs to be done.

#include "PeriodicTask.h" // We connect the class header file to perform periodic tasks.

#include <iostream>

int main(int argc, const char* argv[])
{
    std::cout << "Start program" << std::endl;
    int count = 0;
    // Create a periodic task with a period of 1 second
    PeriodicTask p(boost::chrono::seconds{ 1 }, [&count]() {
        // Display the counter and increment it by one.
        std::cout << count++ << std::endl;
    });

    // Stop the main program flow for 10 seconds so that the periodic task can work 10 times.
    boost::this_thread::sleep_for(boost::chrono::seconds{ 10 });
    std::cout << "End program" << std::endl;
    return 0;
}

Coclusion

As a conclusion I attach the archive with the project.

Periodic.zip

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Comments

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D
March 19, 2019, 9:57 a.m.
Damir

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Last comments
March 16, 2019, 1:55 p.m.
Дмитрий

Спасибо за статью. Давно итересует следующий вопрос: с помощью переменных QMAKE_TARGET_COMPANYQMAKE_TARGET_PRODUCTQMAKE_TARGET_DESCRIPTIONможно задать свойства компилируемой программы, о...
JS
March 12, 2019, 10:19 a.m.
Jean Stefanovich

Большое спасибо за разъяснения!
March 12, 2019, 10:04 a.m.
Евгений Легоцкой

Hello, In fact, this functionality or is not implemented, or is not documented. I'm not sure. But I think, that it should be implemented in Text QML Type. Because of we can write text in...
March 12, 2019, 9:51 a.m.
Евгений Легоцкой

Да вы правы. На самом деле проще через QSqlQueryModel, сколько не пытался использовать эти дженерики типо QSqlTableModel и QSqlRelationalTableModel, то всегда упирался в какие-то их ограничени...
JS
March 12, 2019, 9:47 a.m.
Jean Stefanovich

Единицы измерения лежат там же где и названия продуктов. Просто в таблице ингредиенты нет ещё одного столбца, на который можно было бы установить setRelation. Я в итоге в базе создал ещё один ...
Now discuss on the forum
March 17, 2019, 10:47 p.m.
Евгений Легоцкой

Добрый день. Вот, нашлось у меня немного времени. Делается это через шаблон проектирования наблюдатель. GraphKS_mfvSlup.zip
ЧГ
March 15, 2019, 9:52 p.m.
Чарльз Грин

спасибо, попробую, отпишусь
m
March 15, 2019, 7:41 p.m.
mihamuz

Сори догадался)
n
March 12, 2019, 4:57 p.m.
newbie.works.with.QT

Большооооое спасибо!!!!!Не передать как я вам благодарен, спасибо что всегда отзываетесь.Теперь я смогу продолжить работу в QT!!! (пробую писать бота (Я как вы могли догадаться немного не пр...
March 12, 2019, 1:20 p.m.
BlinCT

Ну так если у вас есть готовая программа так ей и воспользуйтесь. Вы же написали ее вот и пользуйтесь.
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