#include?
#include?
#include?
#include?
#include?
#include?

//#define?PORTNUM?5000
//#define?GROUPIP?“224.0.1.1“

#define?PORTNUM?1900
#define?GROUPIP?“239.255.255.250“

#define?BUFLEN?1024
#define?TESTNUM?10

int?main（）
{
	int?sock_id;
	struct?sockaddr_in?addr?sender;
	struct?ip_mreq?ipmr;
	char?buf[BUFLEN];
	socklen_t?len;
	int?ret;
	int?count;

	/*?Step?1:?open?a?socket?and?bind?*/
	if?（（sock_id?=?socket（AF_INET?SOCK_DGRAM?0））?	{
		perror（“socket?error“）;
		exit（1）;
	}

	memset（（void*）&addr?0?sizeof（addr））;
	addr.sin_family?=?AF_INET;
	addr.sin_addr.s_addr?=?htonl（INADDR_ANY）;
	addr.sin_port?=?htons（PORTNUM）;
	
	if?（bind（sock_id?（struct?sockaddr?*）&addr?sizeof（addr））?	{
		perror（“bind?error“）;
		exit（1）;
	}

	/*?Step?2:?fill?in?a?struct?ip_mreq?*/
	memset（（void*）&ipmr?0?sizeof（ipmr））;
	ipmr.imr_multiaddr.s_addr?=?inet_addr（GROUPIP）;?/*?multicast?group?ip?*/
	ipmr.imr_interface.s_addr?=?htonl（INADDR_ANY）;
	printf（“ip?:%s\n“inet_ntoa（ipmr.imr_interface.s_addr））;
	
	/*?Step?3:?call?setsockopt?with?IP_ADD_MEMBERSHIP?to?support?receiving?multicast?*/
	if?（setsockopt（sock_id?IPPROTO_IP?IP_ADD_MEMBERSHIP?&ipmr?sizeof（ipmr））?	{
		perror（“setsockopt:IP_ADD_MEMBERSHIP“）;
		exit（1）;
	}

	/*?Step?4:?call?recvfrom?to?receive?multicast?packets?*/
	len?=?sizeof（sender）;
	count?=?0;
	while?（count?	{
		ret?=?recvfrom（sock_id?buf?BUFLEN?0?（struct?sockaddr?*）&sender?&len）;
		buf[ret]?=?‘\0‘;
		if?（ret?		{
			perror（“recvfrom?error“）;
			exit（1）;
		}
		printf（“addr?ip?:%s\n“inet_ntoa（ipmr.imr_interface.s_addr））;
		printf（“ip?:%s\n“inet_ntoa（ipmr.imr_interface.s_addr））;
		printf（“%d.?Receive?from?%s:%u\n“?count
		inet_ntoa（sender.sin_addr.s_addr）?ntohs（sender.sin_port））;
		printf（“\tpacket?data:?%s\n“?buf）;
	}

	/*?Step?5:?call?setsockopt?with?IP_DROP_MEMBERSHIP?to?drop?from?multicast?*/
	if?（setsockopt（sock_id?IPPROTO_IP?IP_DROP_MEMBERSHIP?&ipmr?sizeof（ipmr））?	{
		perror（“setsockopt:IP_DROP_MEMBERSHIP“）;
		exit（1）;
	}

	/*?Step?6:?close?the?socket?*/
	close（sock_id）;
	
	return?0;
}

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????7671??2013-05-12?10:01??zb_socket\zb_recv

?????文件???????2227??2013-05-12?10:01??zb_socket\zb_recv.c

?????文件???????7469??2013-05-12?09:36??zb_socket\zb_send

?????文件???????1150??2013-04-24?12:56??zb_socket\zb_send.c

?????文件????????132??2010-08-07?11:05??zb_socket\說明.txt

?????目錄??????????0??2013-07-15?17:15??zb_socket

-----------?---------??----------?-----??----

????????????????18649????????????????????6