#include <stdio.h>
        #include <stdlib.h>
        #include <unistd.h>
        #include <inttypes.h>
        #include <sys/types.h>
        #include <sys/stat.h>
        #include <string.h>
        #include <fcntl.h>
        #include <errno.h>
        #include <termios.h>
        #include <sys/ioctl.h>

        int SerialConnection();
        int serial_fd;



        int main(int argc, char* argv[])
        {
            char buffer[255];       /* Input buffer */
            char *bufptr;           /* Current char in buffer */
            int  nbytes;            /* Number of bytes read */

            if(argc != 2)
            {
                printf( "Usage: %s <Serial Port>n",argv[0]);
                exit(1);
            }

            serial_fd = SerialConnection(argv[1]);//Open serial port
            if(serial_fd < 1)
            {
                printf( "Serial Port Open Failuren");
                exit(1);
            }
            printf( "Serial Port Open Succesfullyn");


            while(1)
            {
                memset(buffer, 0, 255); //clear buffer
                int ELMInit = 1;
                switch(ELMInit)
                {
                case 1:
                    printf( "Request ATZ Reset ELM Adaptern");
                    write(serial_fd, "ATZr", 4);
                    bufptr = buffer;
                    while ((nbytes = read(serial_fd, bufptr, buffer + sizeof(buffer) - bufptr - 1)) > 0)
                    {
                        printf("current buffer %s n",buffer);
                        bufptr += nbytes;
                        if (bufptr[-1] == 'r')
                        {
                            printf("carriage return found %s n",buffer);
                            if(strstr(buffer, "ELM327") != NULL)
                            {
                                printf("success %sn",buffer);
                            }
                            break;
                        }
                        *bufptr = '';
                    }
                    break;

                    default:
                    break;


                }

            }

        }

        int SerialConnection(char *serial_port)
        {
            int fd;
            struct termios options;

            fd = open(serial_port, O_RDWR | O_NOCTTY | O_NDELAY);
            if (fd == -1)
            {
                return -1;
            }
            else
            {
                fcntl(fd, F_SETFL, 0);
                tcgetattr(fd, &options);
                cfsetispeed(&options, B38400);
                cfsetospeed(&options, B38400);
                options.c_cflag &= ~PARENB;                     /* Mask the character size to 8 bits, no parity */
                options.c_cflag &= ~CSTOPB;                     /*1 Stop bit */
                options.c_cflag &= ~CSIZE;
                options.c_cflag |= CS8;                         /* Select 8 data bits */
                options.c_cflag &= ~CRTSCTS;                    /* Disable hardware flow control */
                //options.c_lflag |= ICANON;                        /* Canonical mode*/
                //options.c_lflag |= ~(ICANON | ECHO | ECHOE);  /* Enable data to be processed as Canonical input */
                options.c_cflag |= (CLOCAL | CREAD);            /* Enable the receiver and set local mode */
                tcsetattr(fd, TCSANOW, &options);               /* Set the new options for the port */
            }
            return (fd);
        }