posix多线程--三种基本线程编程模型

本文介绍了三种构建线程解决方案的方式。

 

一、流水线：每个线程执行同一种操作，并把操作结果传递给下一步骤的线程。

代码示例如下：
终端输入一个int值，每个线程将该值加1，并将结果传给下一个线程。

#include<stdio.h>                                                                
#include<pthread.h>
typedef struct stage_tag
 {
          pthread_mutex_t mutex;
          pthread_cond_t cond;
          int data;
          int ready;
          pthread_t tid;
          struct stage_tag *next;
}stage_t;
typedef struct pipe_tag
{
        pthread_mutex_t mutex;
        stage_t *head;
        stage_t *tail;
        int stages;
}pipe_t;
void pipe_send(stage_t *stage,int data)
{
        stage->data =data;
        stage->ready = 1;
        pthread_cond_signal(&stage->cond);
}
void *thread_route(void *arg)
{
        stage_t *stage = (stage_t *)arg;
        while(!stage->ready)
        {
                pthread_cond_wait(&stage->cond,&stage->mutex);
 }
        int data = stage->data+1;
        stage_t *next = stage->next;
        if(next!=NULL)
        {
                pipe_send(next,data);
        }
        return NULL;
}
void create_pipe(pipe_t *pipe,int stages)
{
//      pipe = (pipe_t *)malloc(sizeof(pipe_t));
        pipe->stages = stages;
        int i;
        stage_t *stage;
        stage_t *last;
        for(i=0;i<=stages;i++)
        {
                stage = (stage_t *)malloc(sizeof(stage_t));
                stage->data = i;
                if(i==0)
                {
                        pipe->head = stage;
                }
                if(last!=NULL)
                {
                        last->next = stage;
                }
last = stage;
        }
        last->next=NULL;
        pipe->tail = last;
        for(stage=pipe->head;stage->next!=NULL;stage=stage->next)
        {
                pthread_create(&stage->tid,NULL,thread_route,(void *)stage);
                printf("stage %d\n",stage->data);
        }
/*      free(pipe);
        for(stage=pipe->head;stage!=NULL;stage=stage->next)
        {
                  free(stage);
        }       
        */
}
int main(void)
{
        pipe_t my_pipe;
        long value,result;
        char line[128];
        create_pipe(&my_pipe,10);
        pipe_send(my_pipe.head,5);
        sleep(10);
        printf("result is %d\n",my_pipe.tail->data);
        return 0;
} 

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