Index: xflock4
===================================================================
--- xflock4	(revision 29672)
+++ xflock4	(working copy)
@@ -19,9 +19,15 @@
 #  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #
 
-if test x"`which xscreensaver-command 2>/dev/null`" != x""; then
+if test x"$(which slock 2>/dev/null)" != x"" ; then
+    if ! ( ps -fC xscreensaver | grep $USER ) ; then
+        if ! ( ps -fC gnome-screensaver | grep $USER ) ; then
+            slock
+        fi
+    fi
+elif test x"$(which xscreensaver-command 2>/dev/null)" != x"" ; then
     xscreensaver-command -lock 
-elif test x"`which gnome-screensaver-command 2>/dev/null`" != x""; then
+elif test x"$(which gnome-screensaver-command 2>/dev/null)" != x"" ; then
     gnome-screensaver-command --lock
 else
     xlock $*