一个简单的socket编程demo

原文链接：一个简单的socket编程demo
发布时间：2018-12-16 16:44:03

记录这个demo，相当于是保留一份代码片段，以后可以随时拿来用，验证新的想法。人的大脑是很不靠谱的，经常记错东西，需要保留一个索引，放在这里。

服务端

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```cpp
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <time.h> 

int main(int argc, char *argv[])
{
	if (argc < 3)
	{
		printf("USAGE:./server 127.0.0.1 5555\n");
		return -1;
	}
	//解析参数
	int nPort = atoi(argv[2]);

	struct in_addr addr;
	//得到的是网络字节序的IP
	if (inet_aton(argv[1], &addr) < 0)
	{
		printf("addr[%s] is invalid\n", argv[1]);
		return -1;
	}

    int listenfd = 0, connfd = 0;
    struct sockaddr_in serv_addr; 

    char sendBuff[1025];
    time_t ticks; 

    listenfd = socket(AF_INET, SOCK_STREAM, 0);
    memset(&serv_addr, '0', sizeof(serv_addr));
    memset(sendBuff, '0', sizeof(sendBuff)); 

    serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = addr.s_addr;
    serv_addr.sin_port = htons(nPort); 

    bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)); 

    listen(listenfd, 10); 

    while(1)
    {
        connfd = accept(listenfd, (struct sockaddr*)NULL, NULL); 
		printf("new client connected.\n");
        ticks = time(NULL);
        snprintf(sendBuff, sizeof(sendBuff), "%.24s\r\n", ctime(&ticks));
        write(connfd, sendBuff, strlen(sendBuff)); 

        close(connfd);
        sleep(1);
     }
}  // server.c 服务端

客户端

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```cpp
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <arpa/inet.h> 

int main(int argc, char *argv[])
{
    int sockfd = 0, n = 0;
    char recvBuff[1024];
    struct sockaddr_in serv_addr; 

    if(argc < 3)
    {
        printf("\n Usage: %s 127.0.0.1 9999\n",argv[0]);
        return 1;
    } 

	//解析参数
	int nPort = atoi(argv[2]);

	struct in_addr addr;
	if (inet_aton(argv[1], &addr) < 0)//得到的是网络字节序的IP
	{
		printf("addr[%s] is invalid\n", argv[1]);
		return -1;
	}

    memset(recvBuff, '0',sizeof(recvBuff));
    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        printf("\n Error : Could not create socket \n");
        return 1;
    } 

    memset(&serv_addr, '0', sizeof(serv_addr)); 

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(nPort); 
	serv_addr.sin_addr.s_addr = addr.s_addr;

   /* if(inet_pton(AF_INET, argv[1], &serv_addr.sin_addr)<=0)
    {
        printf("\n inet_pton error occured\n");
        return 1;
    } 这个支持IPv6
*/
    if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
    {
       printf("\n Error : Connect Failed \n");
       return 1;
    } 

    while ( (n = read(sockfd, recvBuff, sizeof(recvBuff)-1)) > 0)
    {
        recvBuff[n] = 0;
        if(fputs(recvBuff, stdout) == EOF)
        {
            printf("\n Error : Fputs error\n");
        }
    } 

    if(n < 0)
    {
        printf("\n Read error \n");
    } 

    return 0;
} // client.c