+2012-03-07 Glenn Morris <rgm@gnu.org>
+
+ * markers.texi (The Region):
+ Briefly mention use-empty-active-region and region-active-p.
+
2012-03-07 Chong Yidong <cyd@gnu.org>
* text.texi (Buffer Contents): Don't duplicate explanation of
relocate them if necessary. This slows processing in a buffer with a
large number of markers. For this reason, it is a good idea to make a
marker point nowhere if you are sure you don't need it any more.
-Unreferenced markers are garbage collected eventually, but until then
-will continue to use time if they do point somewhere.
@cindex markers as numbers
Because it is common to perform arithmetic operations on a marker
@code{push-mark} discards an old mark when it adds a new one.
@end defopt
+@c There is also global-mark-ring-max, but this chapter explicitly
+@c does not talk about the global mark.
+
@node The Region
@section The Region
@cindex region (between point and mark)
mark is active, and there is a valid region in the buffer. This
function is intended to be used by commands that operate on the
region, instead of on text near point, when the mark is active.
+
+A region is valid if it has a non-zero size, or if the user option
+@code{use-empty-active-region} is non-@code{nil} (by default, it is
+@code{nil}). The function @code{region-active-p} is similar to
+@code{use-region-p}, but considers all regions as valid. In most
+cases, you should not use @code{region-active-p}, since if the region
+is empty it is often more appropriate to operate on point.
@end defun
+