Very strange question, program card dead in the serial port set function inside, not come out of __ function

Function: tcsetattr (fd,tcsanow,&newtio)

Open serial port is also successful, one into this serial port Setup function, the program is stuck to death, out of;

If FD is occupied, it must be open is failed, you can use PID to see what resources the process occupies: ls-l/proc/304/fd;

Solve:

I tried a lot of the open parameters, I used the attribute o_noctty to open, accidentally found, no card dead;

Open ("/dev/ttyama3", o_rdwr| o_nonblock| O_noctty); O_noctty: Notify the Linux system that this program will not be the control terminal for this port.