广播编程

host.c：

#include
#include
#include
#include
#include
#include
#include
#include
#include

void main(int argc,char **argv[])
{
   struct sockaddr_in add;
   int fd, fd1, i;
   int len;
   char msg[100] = "i am host\n";
   char buf[100];
   int yes;

   fd = socket(AF_INET, SOCK_DGRAM, 0);
   len = sizeof(add);
   bzero(&add, sizeof(add));
   add.sin_port = htons(5000);
   add.sin_family = AF_INET;
   add.sin_addr.s_addr = htonl(INADDR_ANY);
   bind(fd, (struct sockaddr*)&add, sizeof(add));
   recvfrom(fd, buf, 100, 0, (struct sockaddr *)&add, &len);
   printf("msg recv:%s\n", buf);
}

 

cli.c：

#include
#include
#include
#include
#include
#include
#include
#include
#include

void main(int argc,char **argv[])
{
   struct sockaddr_in add;
   int fd, fd1, i;
   int len;
   int yes = 1;
   char msg[100] = "i am cli\n";
   char buf[100];

   fd = socket(AF_INET, SOCK_DGRAM, 0);

   setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &yes, sizeof(yes));
   bzero(&add, sizeof(add));
   add.sin_port = htons(5000);
   add.sin_family = AF_INET;
   add.sin_addr.s_addr = inet_addr("10.144.15.255");
   sendto(fd,msg, strlen(msg), 0, (struct sockaddr *)&add, sizeof(add));
}

makefile：

LIB = -lsocket -lnsl
all : clean host cli
.PHONY : all
clean :
 -rm *.o core host cli
host : host.o
 cc -o host host.o $(LIB)
host.o : host.c
 cc -c host.c $(LIB)
cli : cli.o
 cc -o cli cli.o $(LIB)
cli.o : cli.c
 cc -c cli.c $(LIB)

与udp程序相比，只是多了红色部分代码。