Variable: window-safe-min-width
window-safe-min-width is a variable defined in window.el.gz.
Value
2
Documentation
The absolute minimum number of columns of a window.
Anything less might crash Emacs.
Source Code
;; Defined in /usr/src/emacs/lisp/window.el.gz
;; This must go to C, finally (or get removed).
(defconst window-safe-min-width 2
"The absolute minimum number of columns of a window.
Anything less might crash Emacs.")