基本概念:
其实UDP的非阻塞也可以理解成和TCP是一样的,都是通过socket的属性去做。
方法一:通过fcntl函数将套接字设置为非阻塞模式。
方法二:通过套接字选项SO_RECVTIMEO设置超时。
方法一源码,编译:g++ udp_server.cpp -o server
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <strings.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
void Perror(const char *s)
{
perror(s);
exit(EXIT_FAILURE);
}
//设置非阻塞
static void setnonblocking(int sockfd) {
int flag = fcntl(sockfd, F_GETFL, 0);
if (flag < 0) {
Perror("fcntl F_GETFL fail");
return;
}
if (fcntl(sockfd, F_SETFL, flag | O_NONBLOCK) < 0) {
Perror("fcntl F_SETFL fail");
}
}
int main()
{
int sockfd;
int port = 9527;
struct sockaddr_in servaddr, cliaddr;
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd == -1) {
Perror("socket failed:");
}
setnonblocking(sockfd);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
servaddr.sin_port = htons(port);
if (bind(sockfd, (sockaddr *)&servaddr, sizeof(servaddr)) == -1) {
Perror("bind failed:");
}
socklen_t len;
for ( ; ; ) {
char mesg[1024] = {};
int n = recvfrom(sockfd, mesg, 1024, 0, (sockaddr *)&cliaddr, &len);
sleep(1);
perror("recvfrom fail: ");
}
return 0;
}
方法二源码,编译:g++ udp_server.cpp -o server
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <strings.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/time.h>
void Perror(const char *s)
{
perror(s);
exit(EXIT_FAILURE);
}
int main()
{
int sockfd;
int port = 9527;
struct sockaddr_in servaddr, cliaddr;
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd == -1) {
Perror("socket failed:");
}
// 设置超时
struct timeval timeout;
timeout.tv_sec = 1;//秒
timeout.tv_usec = 0;//微秒
if (setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) == -1) {
Perror("setsockopt failed:");
}
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
servaddr.sin_port = htons(port);
if (bind(sockfd, (sockaddr *)&servaddr, sizeof(servaddr)) == -1) {
Perror("bind failed:");
}
socklen_t len;
for ( ; ; ) {
char mesg[1024] = {};
int n = recvfrom(sockfd, mesg, 1024, 0, (sockaddr *)&cliaddr, &len);
perror("recvfrom fail: ");
}
return 0;
}
原文出自:http://blog.csdn.net/daiyudong2020/article/details/70039409
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