多线程-生产者消费者模式（1）

这种模型应该也可以归类为生产者消费者模型，但是我觉得这种实现方法效率应该没有用队列来实现效率高。后面再用队列来实现一次。

这个图就是这个程序所要实现的。

先定义两个结构体，thread_sync_t是保存着生产者和消费者共享的资源数组,thread_var是用来记录这个线程应该处理共享资源中哪一个资源的位置。

struct thread_sync_t{    string* imagePath;    bool* collectFinish;    pthread_mutex_t* collectAndSend;    pthread_cond_t* collectReady;};struct thread_var{    int threadIndex;    thread_sync_t* sync;};

一个生产者线程和多个消费者线程，我这里生产者线程是CollectImages，消费者线程是SendImages。
CollectImages每隔1秒，产生张图片，并发出信号，请求发送进程处理。
SendImages处理一张图片需要2秒。
都是些模板代码，没什么好解释的。

对这些线程共享变量的初始化，每个线程都是共享thread_sync_t这个结构体的对象。

    collectThread = new pthread_t[collectThreadCnt];    sendThread = new pthread_t[sendThreadCnt];    threadVar = new thread_var[sendThreadCnt];    InitThreadVar(threadVar);

void InitThreadVar(thread_var* arg){    thread_sync_t* psync = new thread_sync_t;    psync->imagePath = new string[sendThreadCnt];    psync->collectAndSend = new pthread_mutex_t[sendThreadCnt];    psync->collectReady = new pthread_cond_t[sendThreadCnt];    psync->collectFinish = new bool[sendThreadCnt];    for(int i = 0; i < sendThreadCnt; ++i){        pthread_mutex_init(&psync->collectAndSend[i], NULL);        pthread_cond_init(&psync->collectReady[i], NULL);        psync->collectFinish[i] = false;    }    for(int i = 0; i < sendThreadCnt; ++i){        arg[i].threadIndex = i;        arg[i].sync = psync;    }}

全部源代码

#include <iostream>#include "util/DBHelper.h"#include <pthread.h>#include <string>#include <cstring>#include <ctime>#include <sstream>#include <unistd.h>using namespace std;void* CollectImages(void*);void* SendImages(void*);void err_exit(int, string);struct thread_sync_t{    string* imagePath;    bool* collectFinish;    pthread_mutex_t* collectAndSend;    pthread_cond_t* collectReady;};struct thread_var{    //int cameraIndex;    int threadIndex;    thread_sync_t* sync;//    string imagePath;//    bool collectFinish;//    pthread_mutex_t* collectAndSend;//    pthread_cond_t* collectReady;};void InitThreadVar(thread_var*);void DestoryThreadVar(thread_var*);pthread_t* sendThread;pthread_t* collectThread;thread_var* threadVar;int collectThreadCnt = 1;int sendThreadCnt = 10;int main() {    int err;    collectThread = new pthread_t[collectThreadCnt];    sendThread = new pthread_t[sendThreadCnt];    threadVar = new thread_var[sendThreadCnt];    InitThreadVar(threadVar);    for(int i = 0; i < collectThreadCnt; ++i){        err = pthread_create(&collectThread[i], NULL, CollectImages, (void*)threadVar);        if(err != 0){            err_exit(err, "create thread error");        }    }    for(int i = 0; i < sendThreadCnt; ++i){        err = pthread_create(&sendThread[i], NULL, SendImages, (void*)(threadVar + i));        if(err != 0){            err_exit(err, "create thread error");        }    }    while(1){    }    return 0;}void InitThreadVar(thread_var* arg){    thread_sync_t* psync = new thread_sync_t;    psync->imagePath = new string[sendThreadCnt];    psync->collectAndSend = new pthread_mutex_t[sendThreadCnt];    psync->collectReady = new pthread_cond_t[sendThreadCnt];    psync->collectFinish = new bool[sendThreadCnt];    for(int i = 0; i < sendThreadCnt; ++i){        pthread_mutex_init(&psync->collectAndSend[i], NULL);        pthread_cond_init(&psync->collectReady[i], NULL);        psync->collectFinish[i] = false;    }    for(int i = 0; i < sendThreadCnt; ++i){        arg[i].threadIndex = i;        arg[i].sync = psync;    }}void DestoryThreadVar(thread_var* arg){}void* CollectImages(void* arg){    bool cond = false;    while(1){        srand((int)time(0));        for(int threadIndex = 0; threadIndex < sendThreadCnt; ++threadIndex){            thread_var* threadArg = &((thread_var*) arg)[threadIndex];            //cout << "thread: " << threadIndex << " collect image before lock" <<endl;            pthread_mutex_lock(&threadArg->sync->collectAndSend[threadIndex]);            //cout << "thread: " << threadIndex << " collect image lock" <<endl;            int r = rand() % sendThreadCnt;            stringstream ss;            ss << "/home/honkee/Downloads/photo/" << r << ".jpg";            ss >> threadArg->sync->imagePath[threadIndex];            threadArg->sync->collectFinish[threadIndex] = true;            cout << "thread: " << threadIndex << " collect finish: "                    << threadArg->sync->imagePath[threadIndex] << endl <<flush;            pthread_cond_signal(&threadArg->sync->collectReady[threadIndex]);            pthread_mutex_unlock(&threadArg->sync->collectAndSend[threadIndex]);            //cout << "thread: " << threadIndex << " collect image unlock" <<endl;            sleep(1);        }        if(cond){            break;        }    }    printf("collect image thread\n");}void* SendImages(void* arg){    thread_var* threadArg = (thread_var*) arg;    bool cond = false;    while(1){        int threadIndex = threadArg->threadIndex;        //cout << "thread: " << threadIndex << " send image before lock" <<endl;        pthread_mutex_lock(&threadArg->sync->collectAndSend[threadIndex]);        //cout << "thread: " << threadIndex << " send image lock" <<endl;        while(threadArg->sync->collectFinish[threadIndex] == false){            cout << "thread: "<< threadIndex << " waiting..." <<endl <<flush;            pthread_cond_wait(&threadArg->sync->collectReady[threadIndex],                                &threadArg->sync->collectAndSend[threadIndex]);        }        cout << "thread: " << threadIndex << " send finish: "                << threadArg->sync->imagePath[threadIndex] << endl <<flush;        threadArg->sync->collectFinish[threadIndex] = false;        sleep(2);        pthread_mutex_unlock(&threadArg->sync->collectAndSend[threadIndex]);        //cout << "thread: " << threadIndex << " send image unlock" <<endl;        if(cond){            break;        }    }    printf("send image thread\n");}void err_exit(int err, string str){    printf("%d: %s\n", err, str.c_str());    exit(err);}