[SOLVED] how to get number of rows and columns support in screen in linux

somlinux · 07-18-2011, 12:32 AM

In linux terminal; how can we get the number of rows ad columns from linux kernel? I tried from environment variables(LINES,COLUMNS) but, I could not retrieve them as my editor program is a child process to linux terminal process.

b0uncer · 07-18-2011, 01:39 AM

Well, in general obtaining the number of rows and columns of a terminal is not a straightforward task. If you want to play safe, use the "traditional" size 25x80. If you insist, see this, this and this. Put short, the solution depends on what you're exactly working with (are you just using basic things, working with some helper libraries, working on some specific kind of terminal, ...)

somlinux · 07-18-2011, 03:18 AM

Quote:

Originally Posted by b0uncer

Well, in general obtaining the number of rows and columns of a terminal is not a straightforward task. If you want to play safe, use the "traditional" size 25x80. If you insist, see this, this and this. Put short, the solution depends on what you're exactly working with (are you just using basic things, working with some helper libraries, working on some specific kind of terminal, ...)

Thanks for the useful links. (I am implementing an small text editor (academic project) )

David the H. · 07-18-2011, 03:51 AM

tput can tell you.

Code:

tput rows
tput cols

The bash shell also sets LINES and COLUMNS environmental variables, if the shopt option checkwinsize is enabled. But you'll have to manually export them if you want them to be visible to child processes

Code:

shopt -s checkwinsize
export LINES COLUMNS

ta0kira · 07-18-2011, 09:09 AM

Quote:

Originally Posted by somlinux

Thanks for the useful links. (I am implementing an small text editor (academic project) )

Is this in C? You should look at man tty_ioctl to make sure you're using accurate and current ioctl information.
Kevin Barry

ntubski · 07-18-2011, 03:23 PM

Wouldn't ncurses be the more obvious choice for a text editor?

somlinux · 07-18-2011, 11:13 PM

Can we export some variable using c system call??

Quote:

Originally Posted by David the H.

tput can tell you.

Code:

tput rows
tput cols

The bash shell also sets LINES and COLUMNS environmental variables, if the shopt option checkwinsize is enabled. But you'll have to manually export them if you want them to be visible to child processes

Code:

shopt -s checkwinsize
export LINES COLUMNS

somlinux · 07-18-2011, 11:20 PM

thanks, it is a good choice

Quote:

Originally Posted by ntubski

Wouldn't ncurses be the more obvious choice for a text editor?