Windows下UDP编程

在Windows下进行UDP编程，与Linux下有细微的区别，最主要的区别主要有：
1、头文件不同：windows下仅需要导入头文件winsock2.h，而linux需要包含许多头文件；
2、windows下需要打开网络库/启动网络库ws2_32.lib，启动了这个库，这个库里的函数/功能才能使用

接下来是源码：
服务器：

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <WinSock2.h>
#include <string.h>
#include <ws2tcpip.h>  //socklen_t
#pragma comment(lib, "ws2_32.lib")	//库文件

int main(int argc, char **argv) {
    
    
	if (argc < 3) {
    
    
		fprintf(stderr, "Usage:%s <ip> <port>\n", argv[0]);
		exit(1);
	}

	WSADATA wsa_data;
	if (WSAStartup(MAKEWORD(2, 2), &wsa_data) != 0)
	{
    
    
		perror("WSAStartup() error!");
	}

	SOCKET sockfd;
	struct sockaddr_in serveraddr;
	socklen_t addrlen = sizeof(serveraddr);

	if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
    
    
		perror("fail to socket");
		exit(1);
	}

	serveraddr.sin_family = AF_INET;
	serveraddr.sin_addr.s_addr = inet_addr(INADDR_ANY);
	serveraddr.sin_port = htons(atoi(argv[2]));

	if (bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(sockaddr)) == SOCKET_ERROR) {
    
    
		perror("fail to bind");
		exit(1);
	}

	while (1) {
    
    
		char text[32] = "";
		struct sockaddr_in clientaddr;
		if (recvfrom(sockfd, text, sizeof(text), 0, (struct sockaddr *)&clientaddr, &addrlen) == -1) {
    
    
			perror("fail to recvfrom");
			exit(1);
		}

		printf("[%s - %d]: %s\n", inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port), text);

		strcat(text, "*_*");

		if (sendto(sockfd, text, sizeof(text), 0, (struct sockaddr *)&clientaddr, addrlen)) {
    
    
			perror("fail to sendto");
			exit(1);
		}
	}
	return 0;
}

客户端

#include<stdlib.h>
#include<stdio.h>
#include<sys/types.h>
#include<WinSock2.h>
#include<string.h>
#include<ws2tcpip.h>

#pragma comment(lib,"ws2_32.lib")

int main(int argc, char **argv) {
    
    
	/*if (argc < 3) {
		fprintf(stderr, "Usage: %s <ip> <port>", argv[0]);
		exit(1);
	}*/

	WSADATA wsa_data;
	if (WSAStartup(MAKEWORD(2, 2), &wsa_data) != 0)
	{
    
    
		perror("WSAStartup() error!");
	}

	int sockfd;
	struct sockaddr_in serveraddr;
	socklen_t addrlen = sizeof(serveraddr);

	if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
    
    
		perror("fail to socket");
		exit(1);
	}

	/*struct sockaddr_in clientaddr;
	clientaddr.sin_family = AF_INET;
	clientaddr.sin_addr.S_un.S_addr = inet_addr(argv[3]);
	clientaddr.sin_port = htons(atoi(argv[4]));*/

	serveraddr.sin_family = AF_INET;
	serveraddr.sin_addr.S_un.S_addr = inet_addr(argv[1]);
	serveraddr.sin_port = htons(atoi(argv[2]));

	char buf[32] = "";
	while (1) {
    
    
		fputs("insert message(q to quit):", stdout);
		fgets(buf, sizeof(buf), stdin);
		buf[strlen(buf) - 1] = '\0';

		if (sendto(sockfd, buf, sizeof(buf), 0, (struct sockaddr *)&serveraddr, addrlen) == -1) {
    
    
			perror("fail to sendto");
			exit(1);
		}
	}

	closesocket(sockfd);
	return 0;

}