关于socket编程，以下文章写得比较好：http://www.cnblogs.com/xudong-bupt/archive/2013/12/29/3483059.html
1. accept()函数，如果客户端一直没有连接，则服务端阻塞在accept()函数处。
以下是client代码
//============================================================================
// Name : client.cpp
// Author : yjzhuang
// Version :
// Copyright : yjzhuang@corp.netease.com
// Description : Hello World in C++, Ansi-style
//============================================================================ #include <iostream>
#include <sys/select.h>
#include <sys/socket.h>
#include <unistd.h>
#include <pthread.h>
#include <stdio.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string>
#include <string.h>
using namespace std; #define SERVER_IP "127.0.0.1"
#define SERVER_PORT 9090
#define BUFSIZE 1024 int getSocket(){
int fd =socket( AF_INET, SOCK_STREAM, );
cout<<"fd="<<fd<<endl;
if(- == fd){
cout<<"Error, fd is -1"<<endl;
}
return fd;
} /**
* 连接到server端，如果成功，返回fd，如果失败返回-1
*/
int connectServer(){
int fd = getSocket();
cout<<"fd= "<<fd<<endl;
if(- == fd){
cout<<"Error, connectServer() quit"<<endl;
return -;
}
struct sockaddr_in remote_addr; //服务器端网络地址结构体
memset(&remote_addr,,sizeof(remote_addr)); //数据初始化--清零
remote_addr.sin_family=AF_INET; //设置为IP通信
remote_addr.sin_addr.s_addr=inet_addr(SERVER_IP);//服务器IP地址
remote_addr.sin_port=htons(SERVER_PORT); //服务器端口号
int con_result = connect(fd, (struct sockaddr*) &remote_addr, sizeof(struct sockaddr));
if(con_result < ){
cout<<"Connect Error!"<<endl;
return -;
}
cout<<"con_result="<<con_result<<endl;
return fd;
} /**
*** 连接到server端，并且不断往server端发送心跳数据
*/
void* heartBeat(void* arg){
cout<<"Heart bead started!"<<endl;
int fd = connectServer();
if(fd<){
cout<<"Heart bead quit!"<<endl;
return ;
}
char buf[BUFSIZE]; //数据传送的缓冲区
string value = "This is heart beat msg!";
strcpy(buf, value.c_str());
while(true){
cout<<"to write data"<<endl;
cout<<"buf="<<buf<<", len="<<strlen(buf)<<endl;
int write_num = write(fd, buf, strlen(buf));
cout<<"write_num="<<write_num<<endl;
sleep();
}
cout<<"Heart bead finished!"<<endl;
return ;
} /**
*** 创建一个新线程，在新线程里调用heartBeat()函数
*/
void threadCall(){
pthread_t thread;
pthread_create(&thread,NULL,heartBeat,NULL);
pthread_detach(thread);
}
int main() {
cout << "main started" << endl; // prints Hello World!!!
threadCall();
sleep();
cout<<"main finished"<<endl;
return ;
}
以下是server代码
/*
* server.cpp
*
* Created on: 2014年11月14日
* Author: yjzhuang
*/ #include <iostream>
#include <sys/select.h>
#include <sys/socket.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <stdio.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string>
#include <string.h>
using namespace std; #define SERVER_IP "127.0.0.1"
#define SERVER_PORT 9090
#define BUFSIZE 1024 int getSocket(){
int fd =socket( AF_INET, SOCK_STREAM, );
if(- == fd){
cout<<"Error, fd is -1"<<endl;
}
return fd;
} int main(){
int fd = getSocket();
if(fd<){
cout<<"Error in main(), fd<0"<<endl;
}
cout<<"fd="<<fd<<endl;
//----为服务器主线程绑定ip和port------------------------------
struct sockaddr_in local_addr; //服务器端网络地址结构体
memset(&local_addr,,sizeof(local_addr)); //数据初始化--清零
local_addr.sin_family=AF_INET; //设置为IP通信
local_addr.sin_addr.s_addr=inet_addr(SERVER_IP);//服务器IP地址
local_addr.sin_port=htons(SERVER_PORT); //服务器端口号
int bind_result = bind(fd, (struct sockaddr*) &local_addr, sizeof(struct sockaddr));
if(bind_result < ){
cout<<"Bind Error in main()"<<endl;
return -;
}
cout<<"bind_result="<<bind_result<<endl;
//---------------------------------------------
listen(fd, );
struct sockaddr_in remote_addr;
int sin_size=sizeof(struct sockaddr_in);
cout<<"before accept"<<endl;
int new_fd = accept(fd, (struct sockaddr*) &remote_addr, (socklen_t*)&sin_size);
cout<<"after accept"<<endl;
if(new_fd < ){
cout<<"Accept error in main()"<<endl;
return -;
}
cout<<"new_fd accepted is "<<new_fd<<endl;
char buffer[BUFSIZE];
while(true){
cout<<"wait to read data..."<<endl;
int len = read(new_fd, buffer, BUFSIZE);
if(len == ){
cout<<"Read from socket finished"<<endl;
return ;
}else if(len < ){
cout<<"Read from socket error"<<endl;
return -;
}
cout<<"Accept data:"<<buffer<<endl;
sleep();
}
}