libzmq ZMQ_SERVER and ZMQ_CLIENT was not declared in this scope

问题描述:

• 在进行服务器与客户端模式的实验时,发现编译报错:ZMQ_SERVER and ZMQ_CLIENT was not declared in this scope

问题分析

* 依据官方文档,目前ZMQ_SERVER/ZMQ_CLIENT是处于草案阶段(可能不稳定)
* 如果要使用草案阶段的功能,编译libzmq库的时候需要 ./configure --enable-drafts=yes
* 默认哈,处于草案阶段的功能,不提供API接口
* 如果你就是想用的话,也是可以的
* 方法1:在代码里#include "zmq.h"之前加 #define ZMQ_BUILD_DRAFT_API 
* 方法2:编译自己代码的时候加 -D ZMQ_BUILD_DRAFT_API

与这个问题一样:libzmq poller编译报错

功能介绍

官网文档_SC模型

与REQ/REP构成的SC模型区别主要在S端,现在的S端回复C的时候要用到
zmq_msg_routing_id()
zmq_msg_set_routing_id()

使用例子

这是我自己的实验代码,可以参考:

g++ test_zmq_s.cpp -std=c++11 -D ZMQ_BUILD_DRAFT_API -g -lzmq -lpthread  -o s
g++ test_zmq_c.cpp -std=c++11 -D ZMQ_BUILD_DRAFT_API -g -lzmq -lpthread  -o c

• 服务器:

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <unistd.h>
#include <pthread.h>
#include "zmq.h"

void *responder = NULL;//server socket
char SendBuf[10] = {
   0};
void send_msg(zmq_msg_t* old_msg)
{
   
    static int k = 1;
    sprintf(SendBuf,"OKK_%02d", k++);
    zmq_msg_t send;
    uint32_t routing_id = zmq_msg_routing_id (old_msg);
    zmq_msg_init_data(&send, SendBuf, strlen(SendBuf)+1, NULL, NULL);
    zmq_msg_set_routing_id (&send, routing_id);
    zmq_msg_send(&send, responder, 0);
    zmq_msg_close(&send);

    return ;
}

void* server_recv_data(void* arg)
{
   
    int n = 0;

    while(1){
   
        char Buf[2000] = {
   0};
        zmq_msg_t reply;
        zmq_msg_init(&reply);
        int rv = 0;
        //rv 收到的字节数
        rv = zmq_msg_recv(&reply, responder, 0);
        char *data = (char*)zmq_msg_data(&reply);
        //sc buff size不一致
        while(rv>0) {
   
            memset(Buf,0,sizeof(Buf));
            memcpy(Buf, data, sizeof(Buf));
            rv-=sizeof(Buf);
            data+=sizeof(Buf);
            printf("[%s][%d]Server Received data[%d]:%s.\n",__FUNCTION__,__LINE__,rv,Buf);
        }

        zmq_msg_close(&reply);
        //回复客户端
        send_msg(&reply);
    }
    return NULL;
}

int main ()
{
   
    // Prepare our context and socket
    void *context   = zmq_ctx_new();
    responder = zmq_socket(context, ZMQ_SERVER);
    zmq_bind(responder, "tcp://*:5000");
    printf("Server Received Start\n");
    pthread_t tid;
    if (responder)
        pthread_create(&tid, NULL, server_recv_data, NULL);

    while (true) sleep(10);

    zmq_close(responder);
    zmq_ctx_destroy(context);

    return 0;
}

• 客户端

#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include "zmq.h"
#define Buf_Size 10000
/********************************************************
 * 坑: 1 发送的时候,在server没有收到之前SendBuf的空间不能释放
 *       什么意思:如果SendBuf定义在send_msg函数里面,对端将收不到你发的内容
 *     2 发送的时候 size为strlen(SendBuf)+1,字符串要算上\0
 * ******************************************************/
void *requester = NULL;
static int N = 33;
void recv_data()
{
   
    char Buf[Buf_Size] = {
   0};
    zmq_msg_t reply;
    zmq_msg_init(&reply);
    zmq_msg_recv(&reply, requester, 0);
    memcpy(Buf, zmq_msg_data(&reply), sizeof(Buf));
    zmq_msg_close(&reply);
     printf("Received replay:%s\n",Buf);
    return;
}

char SendBuf[Buf_Size] = {
   0};
void send_msg()
{
   
    //char SendBuf[10] = {0};危险
    sprintf(SendBuf,"Hello_%02d", ++N);
    for(int i = 0; i<Buf_Size;i++){
   
        SendBuf[i] = 'A'+(i/1000);
    }
    SendBuf[Buf_Size-1] = 0;

    zmq_msg_t send;
    zmq_msg_init_data(&send, SendBuf, strlen(SendBuf)+1, NULL, NULL);
    zmq_msg_send(&send, requester, 0);
    zmq_msg_close(&send);
    printf("Sending Hello Times:%d.\n", N);

    return ;
}

int main (int argc, char *argv[])
{
   
    // step1 zmq_ctx_new()
    void *context = zmq_ctx_new();

    // step2 create Socket and connect to server
    requester = zmq_socket (context, ZMQ_CLIENT);
    zmq_connect (requester, "tcp://localhost:5000");
    printf("Connecting to port:5000 server.\n");

    // step3 send & recv
    for (int i = 0; i != 10; i++)
    {
   
        sleep(1);
        send_msg();
        recv_data();
    }

    // step4 zmq_close()
    zmq_close(requester);

    // step5 zmq_term()
    zmq_term(context);

    getchar(); 
    return 0;
}