[C++知识库]windows socket编程

windows socket编程，接收一个控制组播包，用来控制对外发出的组播包。其中用到了多线程和socket相关知识。代码如下：

// RadarTest.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "comdef.h"
#include <WINSOCK.H>
#include <stdio.h>
#define HELLO_PORT  3840    
#define HELLO_GROUP "228.3.1.1"    


#define RECV_PORT  9411    
#define RECV_GROUP "234.2.2.2"   

#pragma comment(lib, "WSOCK32.lib")

char HJbuff[1024]={0};
int HJbuff_len=500;
int updateTime=0;


char Recvbuff[1024]={0};
int Recvbuff_len=10;

int global_send_flag=0;

void genHJbuf()
{
	memset(HJbuff,0,1024);
	int _mubiaoNum=10;
	HJbuff[0]=2;
	HJbuff[8]=7;
	HJbuff[29]=_mubiaoNum;
	HJDA_Struct	_hjItem;
	int itemSize=sizeof(HJDA_Struct);
	for(int i=0; i<_mubiaoNum; i++)
	{	
		_hjItem.mubiaohao=i+1;
		_hjItem.mubiaostatus=1;
		_hjItem.mubiaojuli=100.0*updateTime;
		_hjItem.mubiaofangwei=30.0*i;
		_hjItem.mubiaoyangjiao=i*10.0;
		_hjItem.jingxiangsudu=0;
		_hjItem.fangweisudu=0;
		_hjItem.yangjiaosudu=0;

		memcpy((char*)&HJbuff[30+i*47],(char*)&_hjItem,itemSize);	//每个航迹点47个字节

		//memcpy((char*)&_hjItem,(char*)&HJbuff[30+i*47],sizeof(HJDA_Struct));
	}
	updateTime++;
}


int ThreadF0(LPVOID lpParam)
{
	int iRet = 0;
	int i=0;
	WSADATA wsaData;
	WSAStartup(MAKEWORD(2, 2), &wsaData);

	SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);
 
	sockaddr_in addr;
	addr.sin_family = AF_INET;
	//addr.sin_addr.S_un.S_addr = INADDR_ANY;
	addr.sin_addr.S_un.S_addr = inet_addr("192.168.4.169");
	addr.sin_port = htons(RECV_PORT);
 
 	bool bOptval = true;
 	iRet = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char*)&bOptval, sizeof(bOptval));
 	if(iRet != 0){
 		printf("setsockopt fail:%d", WSAGetLastError());
 		return -1;
 	}
 
	iRet = bind(sock, (sockaddr*)&addr, sizeof(addr));
	if(iRet != 0){
		printf("bind fail:%d", WSAGetLastError());
		return -1;
	}
	printf("socket:%d bind success\n", sock);
 
	// 加入组播  
	ip_mreq multiCast;
	//multiCast.imr_interface.S_un.S_addr = INADDR_ANY;
	multiCast.imr_interface.S_un.S_addr = inet_addr("192.168.4.169");
	multiCast.imr_multiaddr.S_un.S_addr = inet_addr(RECV_GROUP);
	iRet = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&multiCast, sizeof(multiCast));
	if(iRet != 0){
		printf("setsockopt fail:%d", WSAGetLastError());
		return -1;
	}
 
	printf("udp group start\n");
 
	int len = sizeof(sockaddr);
	char strRecv[1024] = {0};
	while(true)  
	{     
		memset(strRecv, 0, sizeof(strRecv));
		iRet = recvfrom(sock, strRecv, sizeof(strRecv) - 1, 0, (sockaddr*)&addr, &len);
		if(iRet <= 0){
			printf("recvfrom fail:%d", WSAGetLastError());
			return -1;
		}
		if(iRet>0)
		{
			if((strRecv[1])==1)
			{
				global_send_flag=1;
			}
			else
			{
				global_send_flag=0;
			}
		}
	}  
 
	closesocket(sock);
	WSACleanup();

	return 0;
}


 
int _tmain(int argc, _TCHAR* argv[])   
{    
  WSADATA     wsaData;
  WORD wVersionRequested;
  wVersionRequested = MAKEWORD(1,1);
  // Initialize Windows socket library
  WSAStartup(0x0202, &wsaData);

    struct sockaddr_in addr;    
    int fd;
	int t = 0;

	HANDLE htd0;
	DWORD thrdID0;
	htd0 = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)ThreadF0, (void*)&t, 0, &thrdID0);

    /* create what looks like an ordinary UDP socket */    
    if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0)     
    {    
        perror("create send socket error");    
        exit(1);		
    }

    /* set up destination address */    
    memset(&addr,0,sizeof(addr));    
    addr.sin_family=AF_INET;    
    addr.sin_addr.s_addr=inet_addr(HELLO_GROUP);    
    addr.sin_port=htons(HELLO_PORT);    

    /* now just sendto() our destination! */    
    while (1)    
    {    
		if(global_send_flag==1)
		{
			genHJbuf();
			if (sendto(fd,HJbuff, HJbuff_len, 0, (struct sockaddr *) &addr, sizeof(addr)) < 0)     
			{    
				perror("sendto");    
				exit(1);    
			}    
			printf("Send %d times.\n",updateTime);
			Sleep(50);   
		}
    }  
    return 0;    
}

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