linux C syscall to get number of columns of current terminal?

reishin · 11-02-2004, 11:26 AM

I've been trying to search for a way to get the number of columns of the current terminal in my C program but I can't seem to find a c function that would get me the number of columns. Does anyone know of a built in c function that would get me the number of columns in the current terminal window?

jim mcnamara · 11-02-2004, 11:59 AM

The environment variable COLUMNS is defined at login by stty.

Code:

#include <stdlib.h>

int tty_cols(void)
{
   char *tmp=getenv("COLUMNS");
   if(tmp==NULL) return (-1);
   return(atoi(tmp));
}

reishin · 11-02-2004, 12:05 PM

this way works if the COLUMNS enviroment variable is set but on certain linux distros the COLUMNS environment variable isn't set so I won't be able to get the number of columns that way.

Hko · 11-02-2004, 02:53 PM

Heavily inspired (not to say copied) by kev82's code in this thread:
http://www.linuxquestions.org/questi...threadid=81570

Code:

#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdio.h>

int main()
{
    struct winsize ws;

    ioctl(1, TIOCGWINSZ, &ws);
    printf("Columns: %d\tRows: %d\n", ws.ws_col, ws.ws_row);
    return 0;
}

sd9 · 07-15-2009, 01:59 AM

Quote:

Originally Posted by Hko

Heavily inspired (not to say copied) by kev82's code in this thread:
http://www.linuxquestions.org/questi...threadid=81570

Code:

#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdio.h>

int main()
{
    struct winsize ws;

    ioctl(1, TIOCGWINSZ, &ws);
    printf("Columns: %d\tRows: %d\n", ws.ws_col, ws.ws_row);
    return 0;
}

Works like a charm! Love it!

Thanks a lot!!!