unix多线程，互斥锁和信号灯的应用

来源：互联网发布：40岁淘宝美工编辑：程序博客网时间：2024/05/09 12:39

#include <algorithm>
#include <pthread.h>
#include <semaphore.h>
#include <unistd.h>
#include <queue>
#include <iostream>
#include <string>

using namespace std;

static sem_t my_sem;
static bool done_flag = false;

class DATA
{
public:
        DATA(){ size = 0; pthread_mutex_init(&v_mutex, NULL); }
        ~DATA(){ pthread_mutex_destroy(&v_mutex); }
        void add_at_tail(const string &s){ q_string.push(s); }
        const string& get_at_head(){ return q_string.front(); }
        void del_at_head(){ q_string.pop(); }
        bool is_empty(){ return q_string.empty(); }
        int get_size(){ return q_string.size(); }
        void set_def_size(int n){ size = n; }
        int get_def_size(){ return size; }
public:
        pthread_mutex_t v_mutex;
private:
        queue<string> q_string;
        int size;
};

void* product(void *data)
{
        DATA *p_data = (DATA*)data;
        string q_string;
        char str[ 20 ];
        int v_int = 0;
        do
        {
                memset(str, '/0', sizeof(str));
                sprintf(str, "product %d", v_int++);
                q_string = str;
                pthread_mutex_lock(&(p_data->v_mutex));
                p_data->add_at_tail(q_string);
                pthread_mutex_unlock(&(p_data->v_mutex));
                if (v_int%10 == 0)
                        sem_post(&my_sem);
        } while (p_data->get_size() <= p_data->get_def_size());
        done_flag = true;
        sem_post(&my_sem);
        cout << endl << "OK!" << endl;

return NULL;
}

void* consume(void *data)
{
DATA *p_data = (DATA*)data;
int sem_value = 0;

        do
        {
                if (sem_wait(&my_sem))
                {
                        break;
                }
                sem_getvalue(&my_sem, &sem_value);
                if ((done_flag == true) && (sem_value <= 0))
                        break;
                pthread_mutex_lock(&(p_data->v_mutex));
                cout << "consume " << p_data->get_at_head() << endl;
                p_data->del_at_head();
                pthread_mutex_unlock(&(p_data->v_mutex));
        } while(p_data->is_empty() == false);

return NULL;
}

int main(void)
{
        DATA data;
        int v_pthread_product_id[2];
        int v_pthread_consume_id;
        pthread_t v_pthread_product[2];
        pthread_t v_pthread_consume;
        sem_init(&my_sem, 0, 0);

        for (int i = 0; i < 2; i++)
        {
                data.set_def_size((i+1)*10000);
                v_pthread_product_id[i] = pthread_create(&v_pthread_product[i], NULL, product, (void*)&data);
        }
        // sleep(2);
        v_pthread_consume_id = pthread_create(&v_pthread_consume, NULL, consume, (void*)&data);

        for (int j = 0; j < 2; j++)
        {
                pthread_join(v_pthread_product[j], NULL);
        }
        pthread_join(v_pthread_consume, NULL);
        sem_destroy(&my_sem);

return 0;
}