Linux 【线程池】【单例模式】【读者写者问题】

在Linux环境下，使用线程池和单例模式来解决读者写者问题的示例代码如下：

#include <pthread.h>
#include <stdio.h>
 
// 线程安全的计数器
int counter = 0;
pthread_mutex_t counter_mutex = PTHREAD_MUTEX_INITIALIZER;
 
// 读写锁
pthread_rwlock_t rwlock;
 
// 初始化读写锁
void init_rwlock() {
    pthread_rwlock_init(&rwlock, NULL);
}
 
// 读者上锁
void read_lock() {
    pthread_rwlock_rdlock(&rwlock);
}
 
// 读者解锁
void read_unlock() {
    pthread_rwlock_unlock(&rwlock);
}
 
// 写者上锁
void write_lock() {
    pthread_rwlock_wrlock(&rwlock);
}
 
// 写者解锁
void write_unlock() {
    pthread_rwlock_unlock(&rwlock);
}
 
// 任务函数：写者任务
void writer_task() {
    write_lock();
    // 模拟写操作
    printf("Writer: Performing write operation...\n");
    sleep(1);  // 模拟耗时操作
    printf("Writer: Write operation completed.\n");
    write_unlock();
}
 
// 任务函数：读者任务
void reader_task() {
    read_lock();
    // 模拟读操作
    printf("Reader: Performing read operation...\n");
    sleep(1);  // 模拟耗时操作
    printf("Reader: Read operation completed.\n");
    read_unlock();
}
 
// 线程入口函数
void* thread_entry(void* arg) {
    int task_type = *(int*)arg;
    switch (task_type) {
        case 0:
            writer_task();
            break;
        case 1:
            reader_task();
            break;
    }
    return NULL;
}
 
// 线程池类
class ThreadPool {
public:
    ThreadPool(int size) {
        pool_size = size;
        threads = new pthread_t[pool_size];
        queue = new int[pool_size];  // 使用一个简单的队列模拟任务队列
        for (int i = 0; i < pool_size; ++i) {
            queue[i] = -1;  // 初始化任务队列为空
        }
    }
 
    ~ThreadPool() {
        delete[] threads;
        delete[] queue;
    }
 
    void start() {
        for (int i = 0; i < pool_size; ++i) {
            pthread_create(&threads[i], NULL, &thread_entry, &queue[i]);
        }
    }
 
    void add_task(int task_type) {
        for (int i = 0; i < pool_size; ++i) {
            if (queue[i] == -1) {
                queue[i] = task_type;
                break;
            }
        }
    }
 
private:
    int pool_size;
    pthread_t* threads;
    int* queue;
};
 
// 单例模式的线程池
class ThreadPoolSingleton {
public:
    static ThreadPoolSingleton& get_instance() {
        static ThreadPoolSingleton instance;
        return instance;
    }
 
    void start_pool() {
        pool.start();
    }
 
    void add_writer_task() {
        pool.add_