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交叉编译器：arm-linux-gcc-4.5.4
Linux内核版本：Linux-3.0
主机操作系统：Centos 6.5
开发板：FL2440
温度传感器:ds18b20
注：此程序的客户端是在装有ds18b20模块并有ds18b20驱动的系统上跑的，本人写的ds18b20的
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一、socket图解
socket是“open—write/read—close”模式的一种实现，而在socket编程里面，socket()就是open()函数了。socket编程的流程图示已经很清楚，各个函数的用法这里就懒得说了，也说不好，网上有一堆一堆的专业人士的解释，非专业人士还是直接上代码的比较好。
二、客户端代码：
1 /********************************************************************************* 2 * Copyright: (C) 2016 2013dianxin_3 3 * All rights reserved. 4 * 5 * Filename: mclient.c 6 * Description: This file 7 * 8 * Version: 1.0.0(08/16/2016) 9 * Author: xiaohexiansheng <1392195453@qq.com> 10 * ChangeLog: 1, Release initial version on "08/16/2016 07:16:44 PM" 11 * 12 ********************************************************************************/ 13 #include14 #include 15 #include 16 #include 17 #include 18 #include 19 #include 20 #include 21 #include 22 #include 23 #include 24 #include 25 #include 26 27 #define MAXLINE 4096 28 /******************************************************************************** 29 * Description: 30 * Input Args: 31 * Output Args: 32 * Return Value: 33 ********************************************************************************/ 34 double get_tem(void) //获取温度的函数 35 { 36 int fd; 37 double result = 0; 38 unsigned char buff[2]; 39 unsigned short temp = 0; 40 int flag = 0; 41 42 if ((fd=open("/dev/ds18b20",O_RDWR | O_NDELAY | O_NOCTTY)) < 0) 43 { 44 perror("open device ds18b20 failed.\r\n"); 45 exit(1); 46 } 47 48 printf("open device ds18b20 success.\r\n"); 49 50 read(fd, buff, sizeof(buff)); 51 temp=((unsigned short)buff[1])<<8; 52 temp|=(unsigned short)buff[0]; 53 result=0.0625*((double)temp); 54 close(fd); 55 printf("temperature is %4f \r\n", result); 56 return result; 57 } 58 59 int main (int argc, char **argv) 60 { 61 double temperature; 62 int sockfd; 63 char temp[25]; 64 char sendline[MAXLINE]; 65 struct sockaddr_in servaddr; 66 67 if(argc != 2) //主函数中需要获得服务器的地址作为第二参数 68 { 69 printf("usage: ./client .\n"); 70 return 0; 71 } 72 73 if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) //如果打开失败则打印错误并返回 74 { 75 printf("create socket error: %s(errno: %d).\n", strerror(errno), errno); 76 return 0; 77 } 78 79 memset(&servaddr, 0, sizeof(servaddr)); 80 servaddr.sin_family = AF_INET; 81 servaddr.sin_port = htons(6666); 82 if(inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0) //将点分十进制ip转换为点分二进制ip 83 { 84 printf("inet_pton error for %s.\n", argv[1]); 85 return 0; 86 } 87 88 if(connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0) //建立连接 89 { 90 printf("connect error: %s(errno: %d)\n", strerror(errno), errno); 91 return 0; 92 } 93 94 temperature = get_tem(); //获取温度 95 gcvt(temperature, 4, temp); //将浮点型数转换为字符串 96 memset(sendline, 0, sizeof(sendline)); 97 strcpy(sendline, temp); 98 if(send(sockfd, sendline, strlen(sendline), 0) < 0) 99 {100 printf("send msg error: %s(errno: %d)\n", strerror(errno), errno);101 return 0;102 }103 104 close(sockfd);105 return 0;106 } /* ----- End of main() ----- */
三、服务器端代码
1 #include2 #include 3 #include 4 #include 5 #include 6 #include 7 #include 8 #include 9 #include 10 11 #define MAXLINE 409612 13 int main(int argc, char** argv)14 {15 int n;16 int listenfd;17 int connfd;18 char buff[4096];19 struct sockaddr_in servaddr;20 21 if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ) //打开socket，若失败则打印失败信息并返回22 {23 printf("create socket error: %s(errno: %d)\n",strerror(errno),errno);24 exit(0);25 }26 27 memset(&servaddr, 0, sizeof(servaddr));28 servaddr.sin_family = AF_INET;29 servaddr.sin_addr.s_addr = htonl(INADDR_ANY);30 servaddr.sin_port = htons(6666);31 32 if(bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1)33 {34 printf("bind socket error: %s(errno: %d)\n",strerror(errno),errno);35 exit(0);36 }37 38 if(listen(listenfd, 10) == -1) //监听串口39 {40 printf("listen socket error: %s(errno: %d)\n",strerror(errno),errno);41 exit(0);42 }43 44 printf("======waiting for client's request======\n");45 while(1)46 {47 memset(buff, 0, sizeof(buff));48 time_t rawtime;49 struct tm* timeinfo;50 char timE[80];51 time(&rawtime);52 timeinfo=localtime(&rawtime);53 strftime(timE,80,"%y-%m-%d %I:%M:%S",timeinfo); //获取系统时间54 55 if((connfd = accept(listenfd, (struct sockaddr*)NULL, NULL)) == -1)56 {57 printf("accept socket error: %s(errno: %d)",strerror(errno),errno);58 continue;59 }60 n = recv(connfd, buff, MAXLINE, 0); //从客户端获取数据，并返回数据大小61 strcat(buff, "℃\0");62 printf("the degrees is: %s %s\n", buff, timE);63 close(connfd);64 }65 close(listenfd);66 }