三种发送UDP包的函数

send()的例子：

#include
#include
#include
void Recv()
{
struct sockaddr_in serv_addr;
int sock_fd;
char line[15] = "Hello world!";
int size = 13;
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
serv_addr.sin_port = htons(5000);
sock_fd = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
connect(sock_fd,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
send(sock_fd, line, size, 0);
close(sock_fd);
}

sendto()的例子：

#include
#include
#include
void Sendto()
{
sockaddr_in receiver_addr;
int sock_fd;
char line[15] = "Hello World!";
sock_fd = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
receiver_addr.sin_family = AF_INET;
receiver_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
receiver_addr.sin_port = htons(5000);
sendto(sock_fd, line, 13, 0,(struct sockaddr*)&receiver_addr,sizeof(receiver_addr));
close(sock_fd);
}

sendmsg()的例子：

#include #include
#include
void sendmsg()
{
struct sockaddr_in receiver_addr;
int sock_fd;
char line[15] = "Hello World!";
struct msghdr msg;
struct iovec iov;
sock_fd = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
receiver_addr.sin_family = AF_INET;
receiver_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
receiver_addr.sin_port = htons(5000);
msg.msg_name = &receiver_addr;
msg.msg_namelen = sizeof(receiver_addr);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_iov->iov_base = line;
msg.msg_iov->iov_len = 13;
msg.msg_control = 0;
msg.msg_controllen = 0;
msg.msg_flags = 0;
sendmsg(sock_fd,&msg,0);
close(sock_fd);
}