/*serial server on linux pc */#include <stdio.h>#include <string.h>#include <malloc.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include <termios.h>#include <errno.h>#include <math.h>int spfd;int main(){ char hd[16],*rbuf; int retv,i,ncount=0; struct termios oldtio; int realdata = 0; spfd = open("/dev/ttyS1",O_RDWR|O_NOCTTY); if(spfd<0)	{	 perror("open/dev/ttyS1");	 return -1;	} tcgetattr(spfd,&oldtio); //保存串口的當前設置 cfmakeraw(&oldtio); cfsetispeed(&oldtio,B115200); cfsetospeed(&oldtio,B115200); tcsetattr(spfd,TCSANOW,&oldtio); //選擇新的設置,TCSANOW表示設置立即生效 rbuf = hd; printf("ready for receiving data ....\n"); retv= read(spfd,rbuf,1);  if(retv==-1)	{	 perror("read");	 return -1;	} while( *rbuf!='\0')  {  ncount +=1;  rbuf++;  retv = read(spfd,rbuf,1);  printf("the number received is %d\n",retv);  if (retv== -1)  perror("read");  } for(i=0;i<ncount;i++)  {   realdata += (hd[i]-48)*pow(10,ncount-i-1);  } printf("complete receiving the data %d\n",realdata); close(spfd); return 0;}