Get the size of a character device
#include <sys/ioctl.h>
#define TIOCGSIZE       TIOCGWINSZ
#define TIOCGWINSZ      _IOR('t', 104, struct winsize)
| Argument | Value | 
|---|---|
| fd | A file descriptor that you obtained by opening the device | 
| request | TIOCGWINSZ | 
| Additional argument | A pointer to a struct winsize | 
This command gets the size of a character device (also known as the window size). It's also implemented as the DCMD_CHR_GETSIZE devctl() command.
None.
The winsize structure is defined in <sys/ioctl.h> as follows:
struct winsize {
        unsigned short  ws_row;
        unsigned short  ws_col; 
        unsigned short  ws_xpixel;
        unsigned short  ws_ypixel; 
};