* xdisp.c (decode_mode_spec): Ignore %c and %l constructs in frame

	title.

2 files changed, 33 insertions, 14 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 30cae45ba84..f86c4c6a21c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2006-10-13  Chong Yidong  <cyd@stupidchicken.com>
+
+        * xdisp.c (decode_mode_spec): Ignore %c and %l constructs in frame
+        title.
+
 2006-10-12  Chong Yidong  <cyd@stupidchicken.com>
 
         * keymap.c (Fkey_binding): Check Lisp_Object types before doing
diff --git a/src/xdisp.c b/src/xdisp.c
index 84e585bbd1e..5c017ad70c2 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -17680,12 +17680,20 @@ decode_mode_spec (w, c, field_width, precision, multibyte)
       break;
 
     case 'c':
-      {
-        int col = (int) current_column (); /* iftc */
-        w->column_number_displayed = make_number (col);
-        pint2str (decode_mode_spec_buf, field_width, col);
-        return decode_mode_spec_buf;
-      }
+      /* %c and %l are ignored in `frame-title-format'.
+         (In redisplay_internal, the frame title is drawn _before_ the
+         windows are updated, so the stuff which depends on actual
+         window contents (such as %l) may fail to render properly, or
+         even crash emacs.)  */
+      if (mode_line_target == MODE_LINE_TITLE)
+        return "";
+      else
+        {
+          int col = (int) current_column (); /* iftc */
+          w->column_number_displayed = make_number (col);
+          pint2str (decode_mode_spec_buf, field_width, col);
+          return decode_mode_spec_buf;
+        }
 
     case 'e':
 #ifndef SYSTEM_MALLOC
@@ -17727,11 +17735,16 @@ decode_mode_spec (w, c, field_width, precision, multibyte)
 
     case 'l':
       {
-        int startpos = XMARKER (w->start)->charpos;
-        int startpos_byte = marker_byte_position (w->start);
-        int line, linepos, linepos_byte, topline;
-        int nlines, junk;
-        int height = WINDOW_TOTAL_LINES (w);
+        int startpos, startpos_byte, line, linepos, linepos_byte;
+        int topline, nlines, junk, height;
+
+        /* %c and %l are ignored in `frame-title-format'.  */
+        if (mode_line_target == MODE_LINE_TITLE)
+          return "";
+
+        startpos = XMARKER (w->start)->charpos;
+        startpos_byte = marker_byte_position (w->start);
+        height = WINDOW_TOTAL_LINES (w);
 
         /* If we decided that this buffer isn't suitable for line numbers,
            don't forget that too fast.  */
@@ -23986,9 +23999,10 @@ This variable is not guaranteed to be accurate except while processing
   DEFVAR_LISP ("frame-title-format", &Vframe_title_format,
     doc: /* Template for displaying the title bar of visible frames.
 \(Assuming the window manager supports this feature.)
-This variable has the same structure as `mode-line-format' (which see),
-and is used only on frames for which no explicit name has been set
-\(see `modify-frame-parameters').  */);
+
+This variable has the same structure as `mode-line-format', except that
+the %c and %l constructs are ignored.  It is used only on frames for
+which no explicit name has been set \(see `modify-frame-parameters').  */);
 
   DEFVAR_LISP ("icon-title-format", &Vicon_title_format,
     doc: /* Template for displaying the title bar of an iconified frame.