Patch by Martin.Lorentzson@telia.com.

[bpt/emacs.git] / lispref / modes.texi

diff --git a/lispref/modes.texi b/lispref/modes.texi
index bbeb084..7ac30f2 100644 (file)
--- a/lispref/modes.texi
+++ b/lispref/modes.texi
@@ -1058,18 +1058,25 @@ line and column numbers, since those depend on point and on how the
 window is scrolled.  @code{header-line-format} is used likewise for
 header lines.
 
-  The mode line and header line of a window are normally updated
-whenever a different buffer is shown in the window, or when the buffer's
-modified-status changes from @code{nil} to @code{t} or vice-versa.  If
-you modify any of the variables referenced by @code{mode-line-format}
-(@pxref{Mode Line Variables}), or any other variables and data
-structures that affect how text is displayed (@pxref{Display}), you may
-want to force an update of the mode line so as to display the new
-information or display it in the new way.
+  For efficiency, Emacs does not recompute the mode line and header
+line of a window in every redisplay.  It does so when circumstances
+appear to call for it---for instance, if you change the window
+configuration, switch buffers, narrow or widen the buffer, scroll, or
+change the buffer's modification status.  If you modify any of the
+variables referenced by @code{mode-line-format} (@pxref{Mode Line
+Variables}), or any other variables and data structures that affect
+how text is displayed (@pxref{Display}), you may want to force an
+update of the mode line so as to display the new information or
+display it in the new way.
 
 @c Emacs 19 feature
 @defun force-mode-line-update
 Force redisplay of the current buffer's mode line and header line.
+The next redisplay will update the mode line and header line based on
+the latest values of all relevant variables.
+
+This function also forces recomputation of the menu bar menus
+and the frame title.
 @end defun
 
   The mode line is usually displayed in inverse video; see
@@ -1824,8 +1831,15 @@ Find text by calling @var{function}, and highlight the matches
 it finds using @code{font-lock-keyword-face}.
 
 When @var{function} is called, it receives one argument, the limit of
-the search.  It should return non-@code{nil} if it succeeds, and set the
-match data to describe the match that was found.
+the search; it should searching at point, and not search beyond the
+limit.  It should return non-@code{nil} if it succeeds, and set the
+match data to describe the match that was found.  Returning @code{nil}
+indicates failure of the search.
+
+Fontification will call @var{function} repeatedly with the same limit,
+and with point where the previous invocation left it, until
+@var{function} fails.  On failure, @var{function} need not reset point
+in any particular way.
 
 @item (@var{matcher} . @var{match})
 In this kind of element, @var{matcher} is either a regular