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When a line of text extends beyond the right edge of a window, Emacs can continue the line (make it “wrap” to the next screen line), or truncate the line (limit it to one screen line). The additional screen lines used to display a long text line are called continuation lines. Continuation is not the same as filling; continuation happens on the screen only, not in the buffer contents, and it breaks a line precisely at the right margin, not at a word boundary. See Filling.
On a graphical display, tiny arrow images in the window fringes indicate truncated and continued lines (see Fringes). On a text terminal, a `$' in the rightmost column of the window indicates truncation; a `\' on the rightmost column indicates a line that “wraps.” (The display table can specify alternate characters to use for this; see Display Tables).
This buffer-local variable controls how Emacs displays lines that extend beyond the right edge of the window. The default is
nil, which specifies continuation. If the value is non-nil, then these lines are truncated.If the variable
truncate-partial-width-windowsis non-nil, then truncation is always used for side-by-side windows (within one frame) regardless of the value oftruncate-lines.
This variable is the default value for
truncate-lines, for buffers that do not have buffer-local values for it.
This variable controls display of lines that extend beyond the right edge of the window, in side-by-side windows (see Splitting Windows). If it is non-
nil, these lines are truncated; otherwise,truncate-linessays what to do with them.
When horizontal scrolling (see Horizontal Scrolling) is in use in a window, that forces truncation.
If your buffer contains very long lines, and you use
continuation to display them, just thinking about them can make Emacs
redisplay slow. The column computation and indentation functions also
become slow. Then you might find it advisable to set
cache-long-line-scans to t.
If this variable is non-
nil, various indentation and motion functions, and Emacs redisplay, cache the results of scanning the buffer, and consult the cache to avoid rescanning regions of the buffer unless they are modified.Turning on the cache slows down processing of short lines somewhat.
This variable is automatically buffer-local in every buffer.