Provided by: xserver-xephyr_1.11.4-0ubuntu9_i386 bug


       Xephyr - X server outputting to a window on a pre-existing X display


       Xephyr [:display] [option ...]


       Xephyr  is  a  kdrive server that outputs to a window on a pre-existing
       "host" X display.  Think Xnest but with support for  modern  extensions
       like composite, damage and randr.

       Unlike  Xnest which is an X proxy, i.e.  limited to the capabilities of
       the host X server, Xephyr is a real X server  which  uses  the  host  X
       server window as "framebuffer" via fast SHM XImages.

       It  also  has  support  for  "visually"  debugging  what  the server is


       The server accepts all the  standard  options  of  Xserver(1)  and  the
       following additional options:

       -screen widthxheight
               sets the screen size.

       -parent id
               uses  exiting  window  id  .   If  a -screen argument follows a
               -parent argument,  this  screen  is  embedded  into  the  given

               set 'cursor acceleration': The host's cursor is reused. This is
               only really there to aid debugging by  avoiding  server  paints
               for the cursor. Performance improvement is negligible.


       Send  a  SIGUSR1  to the server (e.g. pkill -USR1 Xephyr) to toggle the
       debugging mode.  In this mode red  rectangles  are  painted  to  screen
       areas  getting  painted  before painting the actual content.  The delay
       between this can be altered by setting a  XEPHYR_PAUSE  env  var  to  a
       value in micro seconds.


       o Rotated displays are currently updated via full blits. This is slower
         than a normal orientated display. Debug mode will therefore not be of
         much use rotated.

       o The '-host-cursor' cursor is static in its appearance.

       o The  build gets a warning about 'nanosleep'. I think the various '-D'
         build flags are causing this. I haven't figured as yet  how  to  work
         round it. It doesn't appear to break anything however.

       o Keyboard handling is basic but works.

       Mouse button 5 probably won't work.


       X(7), Xserver(1)


       Matthew Allum <> 2004