hi, i find a very strange thing, i use QString::number ( double n, char format = 'g', int precision = 6 ) to show a double type data, the program is run in PC normal, but it run in ARM board, it show -0, and then the program is die, the cpu is up to 85%. but when i use QString::number ( int n, int base = 10 ) , is mean show int type data, the program run in PC or ARM board is well. this is why, and have any method to show double type. thanks.