What is termios.TIOCGWINSZ

Question

I want to get the size of the terminal. I am using this functionality:

import sys, struct, fcntl, termios

s = struct.pack('HHHH', 0, 0, 0, 0)
t = fcntl.ioctl(sys.stdout.fileno(), termios.TIOCGWINSZ, s)
print(struct.unpack('HHHH', t))

But what on earth is termios.TIOCGWINSZ?

Answer 1

It is a magic constant determined by the system you are running on resp. by the terminal driver.

In combination with ioctl(), it serves to tell exectly what you want, in your case call IOCtl to Get the Window Size. Thus the name TIOCGWINSZ, IOCtl to Get the WINdow SiZe.

This bit of documentation might help you clear things up.