UART to Arduino Raspberry Pi

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <termios.h>

#include <sys/types.h>
#include <sys/stat.h>

//Raspberry Pi to Arduino UART
//Takes one argument and sends it over the UART as a string
//Uart /dev/ttyAMA0 is setup and settings are not restored.

int main(int argc, char ** argv) {
  if(argc == 2){
    printf("send: %s\n", argv[1]);
  } else {
    perror("wrong number of args");
    return -1;
  }

  int fd;
  // Open the Port. We want read/write, no "controlling tty" status, and open it no matter what state DCD is in
  fd = open("/dev/ttyAMA0", O_WRONLY | O_NOCTTY | O_NDELAY | O_NONBLOCK);
  if (fd == -1) {
    perror("open_port: Unable to open /dev/ttyAMA0 - ");
    return(-1);
  }

  // Turn off blocking for reads, use (fd, F_SETFL, FNDELAY) if you want that
  //fcntl(fd, F_SETFL, 0);

  //Set the baud rate
  struct termios options;
  tcgetattr(fd, &options);
  cfsetispeed(&options, B9600);
  cfsetospeed(&options, B9600);
  //Set flow control and all that
  options.c_cflag = B9600 | CS8 | CLOCAL | CREAD;
  options.c_iflag = IGNPAR | ICRNL;
  options.c_oflag = 0;
  //Flush line and set options
  tcflush(fd, TCIFLUSH);
  tcsetattr(fd, TCSANOW, &options);

  //set characters
  char* strOut;
  int len = asprintf(&strOut, "%s\n", argv[1]);

  // Write to the port
  int n = write(fd, strOut, len);
  if (n < 0) {
    perror("error writing");
    return -1;
  }

  // Don't forget to clean up
  close(fd);
  return 0;
}
//END OF FILE