#include <stdio.h>#include <errno.h>#include <stdlib.h>#include <sys/time.h>#include <sys/types.h>#include <fcntl.h>#include <unistd.h>#include <sys/ioctl.h>#include <rtl_fifo.h>int main(int argc,char ** argv){	int fd0;	int dc=10;	if ((fd0 = open("/dev/rtf0", O_WRONLY)) < 0) {		fprintf(stderr, "Error opening /dev/rtf0\n");		exit(1);	}	while(dc!=0){		printf("Duty Cycle [10-90%%]: ");		scanf("%d",&dc);		write(fd0, &dc, sizeof(dc));		printf("Duty cycle set to %d %%\n", dc);		fflush(stdout);	}	return 0;}