#include <unistd.h>#include <sys/socket.h>#include <sys/types.h>#include <netinet/in.h>#include <stdio.h>#include <errno.h>#include <signal.h>void sig_handle(int signum){	return;}int main(int argc,char *argv[]){		char buffer[512];	int bordcast_socket;	int read_count=0;	int addr_len=sizeof(struct sockaddr);	struct sockaddr_in  addr_info,addr_net;	int opt=1;	if(argc!=2)	{		printf("Use page boradcast <ip address>\n");		return -1;	}	addr_info.sin_family=AF_INET;	addr_info.sin_addr.s_addr=inet_addr(argv[1]);	addr_info.sin_port=htons(5555);	bordcast_socket=socket(AF_INET,SOCK_DGRAM,0);	if(bordcast_socket<0)	{		perror("bordcast_socket");		return -1;	}	signal(SIGALRM,sig_handle);	setsockopt(bordcast_socket,SOL_SOCKET,SO_BROADCAST,&opt,sizeof(opt));	while(fgets(buffer,sizeof(buffer),stdin)!=NULL)	{		sendto(bordcast_socket,buffer,strlen(buffer),0,(struct sockaddr *)&addr_info,addr_len);		alarm(5);		memset(buffer,0,sizeof(buffer));		for (; ; )		{			read_count=recvfrom(bordcast_socket,buffer,sizeof(buffer),0,(struct sockaddr *)&addr_net,&addr_len);			if(read_count<0 && errno==EINTR)			{				continue;			}			else			{				printf("from %s\n",inet_ntoa(addr_net.sin_addr));			}		}			}	return 0;}