Tty ioctl commands are a subset of the ioctl() calls, which can perform a variety of functions on tty devices. fd shall be an open file descriptor referring to a terminal device.
The following ioctl()s are provided:
Get the size attributes of the terminal or pseudo-terminal identified by
fd. On entry, argp shall reference
a winsize structure.
On return, the structure will have
On success, 0 is returned.
On error, -1 is returned and
the global variable
errno is set appropriately.
fd is not a valid descriptor.
argp references an inaccessible memory area.
request and argp are not valid.