zmqPUBSUB模式传输（C）

　　运行系统：centos7
　　安装依赖：yum -y install wget wget https://dl.fedoraproject.org/pub/epel/7/x86_64/Packages/e/epel-release-7-14.noarch.rpm rpm -ivh epel-release-7-14.noarch.rpm  # 查看所有可安装的zmq依赖 yum search zmq # 安装 yum -y install czmq-devel
　　API： http://api.zeromq.org/
　　server端：#include  #include  #include  #include  #include  #include  #include  #include   using namespace std;  int s_send(void *socket, char const *string) {     // 初始化一个zmq_msg_t对象, 分配的大小为string的大小     zmq_msg_t msg;     zmq_msg_init_size(&msg, strlen(string));     memcpy(zmq_msg_data(&msg), string, strlen(string));     // 发送数据     zmq_msg_send(&msg, socket, 0);     // 关闭zmq_msg_t     zmq_msg_close(&msg); }  int main() {     // 初始化上下文     void *context = zmq_ctx_new();     // 创建、绑定套接字     void *publisher = zmq_socket(context, ZMQ_PUB);     // 绑定到tcp节点     int rc = zmq_bind(publisher, ＂tcp://*:5555＂);     assert(rc == 0);      std::cout << ＂start send data＂ << std::endl;     char const *string = ＂hello world＂;     while(1) {         s_send(publisher, string);         sleep(1);     }     zmq_close(publisher);     zmq_ctx_destroy(context); }
　　client端#include  #include  #include  #include  #include  #include  #include   using namespace std;  char *s_recv(void *socket) {     // 创建zmq_msg_t对象接收数据     zmq_msg_t msg;     zmq_msg_init(&msg);      int size = zmq_msg_recv(&msg, socket, 0);     if (size == -1) {         return NULL;     }      // 将zmq_msg_t对象中的数据保存到字符串中     char *string = (char*)malloc(size + 1);     memcpy(string, zmq_msg_data(&msg), size);     zmq_msg_close(&msg);     string[size] = 0;      return string; }  int main() {     // 初始化上下文     void *context = zmq_ctx_new();      // 创建套接字、连接发布者     void *subscriber = zmq_socket(context, ZMQ_SUB);     int rc = zmq_connect(subscriber, ＂tcp://localhost:5555＂);     assert(rc == 0);      // 设置过滤器，指定需要接收什么类型的消息     char const *filter = ＂MDIndexSnapshot＂;      rc = zmq_setsockopt(subscriber, ZMQ_SUBSCRIBE, filter, strlen(filter));     assert(rc == 0);      std::cout << ＂start recv data＂ << std::endl;     while(1) {         char *string = s_recv(subscriber);         std::cout << string << std::endl;         free(string);     } }
　　运行命令：# 服务端 g++ server.cpp -o server -lzmq ./server  # 客户端 g++ client.cpp -o client -lzmq ./client