Variable: truncate-lines
truncate-lines is a customizable and buffer-local variable defined in
buffer.c.
Documentation
Non-nil means do not display continuation lines.
Instead, give each line of text just one screen line.
Note that this is overridden by the variable
truncate-partial-width-windows if that variable is non-nil
and this buffer is not full-frame width.
Minibuffers set this variable to nil.
Don't set this to a non-nil value when visual-line-mode(var)/visual-line-mode(fun) is
turned on, as it could produce confusing results.
Probably introduced at or before Emacs version 1.7.
Source Code
// Defined in /usr/src/emacs/src/buffer.c
DEFVAR_PER_BUFFER ("truncate-lines", &BVAR (current_buffer, truncate_lines), Qnil,
doc: /* Non-nil means do not display continuation lines.
Instead, give each line of text just one screen line.
Note that this is overridden by the variable
`truncate-partial-width-windows' if that variable is non-nil
and this buffer is not full-frame width.
Minibuffers set this variable to nil.
Don't set this to a non-nil value when `visual-line-mode' is
turned on, as it could produce confusing results. */);