ttyio

Name

ttyio -- tty ioctl commands

Synopsis

#include <sys/ioctl.h>
#include <fcntl.h>

int ioctl(int fd, unsigned long request, int * argp);

Description

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:

TIOCGWINSZ 

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 ws_row set to the number of rows of text (i.e. lines of text) that can be viewed on the device, and ws_col set to the number of columns (i.e. text width).

Note: The number of columns stored in ws_col assumes that the terminal device is using a mono-spaced font.

Return Value

On success, 0 is returned. On error, -1 is returned and the global variable errno is set appropriately.

Errors

EBADF 

fd is not a valid descriptor.

EFAULT 

argp references an inaccessible memory area.

EINVAL 

request and argp are not valid.