Reading from the /dev/ttyUSB1

hi guys,

i working on school project right , working arduino board mega.

i set arduino board sense when there connection closed on board. when connection closed, arduino board executes command "serial.println(sensorvalue, dec);" , prints 1 serial monitor.

from understand, when command executed arduino board writing virtual serial port. "1" shows on serial monitor, when try read in c code receive 0.

my code posted below. insight how read output arduino board?


this c code:

code: [select]


  #include <stdio.h>   /* standard input/output definitions */
   #include <string.h>  /* string function definitions */
   #include <unistd.h>  /* unix standard function definitions */
   #include <fcntl.h>   /* file control definitions */
   #include <errno.h>   /* error number definitions */
   #include <termios.h> /* posix terminal control definitions */


   int main(void)
   {
     int fd; /* file descriptor port */
     int get;
     get = 5;

     fd = open("/dev/ttyusb1", o_rdwr | o_noctty | o_ndelay);
     if (fd == -1)
     {
      //could not open port.
     perror("open_port: unable open /dev/ttys0 - ");
     }
     else
     {

       struct termios options;

      //get current options port...
      tcgetattr(fd, &options);

      //set baud rates 19200...
      cfsetispeed(&options, b9600);
      cfsetospeed(&options, b9600);

      //enable receiver , set local mode...
      options.c_cflag |= (clocal | cread);

      //set new options port...
      tcsetattr(fd, tcsanow, &options);

       while(1){
       delay(500);  
     get = fcntl(fd, f_setfl, 0);
       //get = fcntl(fd, f_setfl, fndelay);
       printf("read: %d\n",get);
       }
   
     }
   
       return (fd);
   }


try usb0

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