如何在 C++ 中为需要访问资源池中的两个不同资源的线程管理线程同步

问：

该程序模拟访问不同资源的多个线程。 我有一个资源池，在我的情况下是一个布尔数组： 我还创建了 6 个不同的线程，它们都需要一次访问其中两个资源：bool res[6] = {1, 1, 1, 1, 1, 1};

T1 -> needs res[0] and res[1]
T2 -> needs res[1] and res[2]
T3 -> needs res[2] and res[3]
T4 -> needs res[3] and res[4]
T5 -> needs res[4] and res[5]
T6 -> needs res[0] and res[5]

当线程使用资源时，它会将布尔值设置为 0，并在完成后恢复为 1。例如：T1 将 res[0] 和 res[1] 设置为 0，“使用它”，然后将两者设置回 1。

我不确定如何使用互斥锁或信号量来防止竞争条件。

显而易见但缓慢的方法是，当线程使用两个资源时，使用互斥锁来锁定整个部分，并在完成后将其解锁，从而防止任何其他线程占用任何资源。这样做的问题是一些线程应该能够同时运行，例如：T1 和 T3 不共享共同的资源，因此应该能够同时执行这些操作。另一方面，T1 和 T2 在共享 res[1] 时不应该同时运行。任何帮助都是值得赞赏的！

编辑：这是我尝试过为每个资源使用信号量的东西，我认为这个解决方案有效，但我可能是错的：

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <string>
#include <sys/types.h>
#include <unistd.h>
#include <thread>
#include <vector>
#include <semaphore>
#include <chrono>
#include <syncstream>

bool el1[6]={1,1,1,1,1,1};

const int64_t tempsCreationObjetsMS = 3000;

std::binary_semaphore sem0{0}, sem1{0}, sem2{0}, sem3{0}, sem4{0}, sem5{0};

void creer_thread(std::string nom)
{
    if(nom == "coupe")
    {
        std::osyncstream(std::cout) << "Je suis le thread " << nom << std::endl;
    
        if (el1[0] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 0" << std::endl;
            sem0.acquire();
        }
        if (el1[1] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 1" << std::endl;
            sem1.acquire();
        }

        el1[0] = 0;
        el1[1] = 0;

        std::osyncstream(std::cout) << nom << " en creation." << std::endl;
        std::this_thread::sleep_for(std::chrono::milliseconds(tempsCreationObjetsMS));
        std::osyncstream(std::cout) << nom << " cree." << std::endl;

        el1[0] = 1;
        el1[1] = 1;

        sem0.release();
        sem1.release();
    }
    else if(nom=="epee")
    {
        std::osyncstream(std::cout) << "Je suis le thread " << nom << std::endl;

        if (el1[1] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 1" << std::endl;
            sem1.acquire();
        }
        if (el1[2] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 2" << std::endl;
            sem2.acquire();
        }

        el1[1] = 0;
        el1[2] = 0;

        std::osyncstream(std::cout) << nom << " en creation." << std::endl;
        std::this_thread::sleep_for(std::chrono::milliseconds(tempsCreationObjetsMS));
        std::osyncstream(std::cout) << nom << " cree." << std::endl;
        el1[1] = 1;
        el1[2] = 1;

        sem1.release();
        sem2.release();
    }
    else if(nom=="chandelier")
    {
        std::osyncstream(std::cout) << "Je suis le thread " << nom << std::endl;

        if (el1[2] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 2" << std::endl;
            sem2.acquire();
        }
        if (el1[3] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 3" << std::endl;
            sem3.acquire();
        }

        el1[2] = 0;
        el1[3] = 0;
        
        std::osyncstream(std::cout) << nom << " en creation." << std::endl;
        std::this_thread::sleep_for(std::chrono::milliseconds(tempsCreationObjetsMS));
        std::osyncstream(std::cout) << nom << " cree." << std::endl;

        el1[2] = 1;
        el1[3] = 1;

        sem2.release();
        sem3.release();
    }
    else if(nom=="bague")
    {
        std::osyncstream(std::cout) << "Je suis le thread " << nom << std::endl;

        if (el1[3] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 3" << std::endl;
            sem3.acquire();
        }
        if (el1[4] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 4" << std::endl;
            sem4.acquire();
        }

        el1[3] = 0;
        el1[4] = 0;

        std::osyncstream(std::cout) << nom << " en creation." << std::endl;
        std::this_thread::sleep_for(std::chrono::milliseconds(tempsCreationObjetsMS));
        std::osyncstream(std::cout) << nom << " cree." << std::endl;

        el1[3] = 1;
        el1[4] = 1;

        sem3.release();
        sem4.release();
    }
    else if(nom=="table")
    {
        std::osyncstream(std::cout) << "Je suis le thread " << nom << std::endl;

        if (el1[4] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 4" << std::endl;
            sem4.acquire();
        }
        if (el1[5] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 5" << std::endl;
            sem5.acquire();
        }

        el1[4] = 0;
        el1[5] = 0;

        std::osyncstream(std::cout) << nom << " en creation." << std::endl;
        std::this_thread::sleep_for(std::chrono::milliseconds(tempsCreationObjetsMS));
        std::osyncstream(std::cout) << nom << " cree." << std::endl;

        el1[4] = 1;
        el1[5] = 1;

        sem4.release();
        sem5.release();
    }
    else if(nom=="porte")
    {
        std::osyncstream(std::cout) << "Je suis le thread " << nom << std::endl;

        if (el1[0] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 0" << std::endl;
            sem0.acquire();
        }
        if (el1[5] != 1)
        {
            std::osyncstream(std::cout) << nom << " en attente de la resource 5" << std::endl;
            sem5.acquire();
        }

        el1[0] = 0;
        el1[5] = 0;
        
        std::osyncstream(std::cout) << nom << " en creation." << std::endl;
        std::this_thread::sleep_for(std::chrono::milliseconds(tempsCreationObjetsMS));
        std::osyncstream(std::cout) << nom << " cree." << std::endl;

        el1[0] = 1;
        el1[5] = 1;

        sem0.release();
        sem5.release();
    }
}

int main(void)
{
    std::thread th1(creer_thread,"coupe");
    std::thread th2(creer_thread,"epee");
    std::thread th3(creer_thread,"chandelier");
    std::thread th4(creer_thread,"bague");
    std::thread th5(creer_thread,"table");
    std::thread th6(creer_thread,"porte");

    th1.join();
    th2.join();
    th3.join();
    th4.join();
    th5.join();
    th6.join();
}