path: root/x11vnc/x11vnc.1

.\" This file was automatically generated from x11vnc -help output.
.TH X11VNC "1" "February 2005" "x11vnc " "User Commands"
.SH NAME
x11vnc - allow VNC connections to real X11 displays
         version: 0.7.1, lastmod: 2005-02-22
.SH SYNOPSIS
.B x11vnc
[OPTION]...
.SH DESCRIPTION
.PP
Typical usage is:
.IP
Run this command in a shell on the remote machine "far-host"
with X session you wish to view:
.IP
x11vnc -display :0
.IP
Then run this in another window on the machine you are sitting at:
.IP
vncviewer far-host:0
.PP
Once x11vnc establishes connections with the X11 server and starts listening
as a VNC server it will print out a string: PORT=XXXX where XXXX is typically
5900 (the default VNC server port).  One would next run something like
this on the local machine: "vncviewer hostname:N" where "hostname" is
the name of the machine running x11vnc and N is XXXX - 5900, i.e. usually
"vncviewer hostname:0".
.PP
By default x11vnc will not allow the screen to be shared and it will exit
as soon as the client disconnects.  See \fB-shared\fR and \fB-forever\fR below to override
these protections.  See the FAQ on how to tunnel the VNC connection through
an encrypted channel such as 
.IR ssh (1).
.PP
For additional info see: http://www.karlrunge.com/x11vnc/
and  http://www.karlrunge.com/x11vnc/#faq
.PP
Rudimentary config file support: if the file $HOME/.x11vncrc exists then each
line in it is treated as a single command line option.  Disable with \fB-norc.\fR
For each option name, the leading character "-" is not required.  E.g. a
line that is either "forever" or "\fB-forever\fR" may be used and are equivalent.
Likewise "wait 100" or "\fB-wait\fR \fI100\fR" are acceptable and equivalent lines.
The "#" character comments out to the end of the line in the usual way.
Leading and trailing whitespace is trimmed off.  Lines may be continued with
a "\\" as the last character of a line (it becomes a space character).
.PP
.SH OPTIONS

.PP
\fB-display\fR \fIdisp\fR
.IP
X11 server display to connect to, usually :0.  The X
server process must be running on same machine and
support MIT-SHM.  Equivalent to setting the DISPLAY
environment variable to \fIdisp\fR.
.PP
\fB-auth\fR \fIfile\fR
.IP
Set the X authority file to be \fIfile\fR, equivalent to
setting the XAUTHORITY environment variable to \fIfile\fR
before startup.  Same as \fB-xauth\fR file.  See 
.IR Xsecurity (7)
,
.IR xauth (1)
man pages for more info.
.PP
\fB-id\fR \fIwindowid\fR
.IP
Show the window corresponding to \fIwindowid\fR not
the entire display.  New windows like popup menus,
transient toplevels, etc, may not be seen or may be
clipped.  Disabling SaveUnders or BackingStore in the
X server may help show them.  x11vnc may crash if the
window is initially partially obscured, changes size,
is iconified, etc.  Some steps are taken to avoid this
and the \fB-xrandr\fR mechanism is used to track resizes.  Use
.IR xwininfo (1)
to get the window id, or use "\fB-id\fR \fIpick\fR"
to have x11vnc run 
.IR xwininfo (1)
for you and extract
the id.  The \fB-id\fR option is useful for exporting very
simple applications (e.g. the current view on a webcam).
.PP
\fB-sid\fR \fIwindowid\fR
.IP
As \fB-id,\fR but instead of using the window directly it
shifts a root view to it: this shows SaveUnders menus,
etc, although they will be clipped if they extend beyond
the window.
.PP
\fB-flashcmap\fR
.IP
In 8bpp indexed color, let the installed colormap flash
as the pointer moves from window to window (slow).
.PP
\fB-notruecolor\fR
.IP
For 8bpp displays, force indexed color (i.e. a colormap)
even if it looks like 8bpp TrueColor (rare problem).
.PP
\fB-visual\fR \fIn\fR
.IP
Experimental option: probably does not do what you
think.  It simply *forces* the visual used for the
framebuffer; this may be a bad thing... (e.g. messes
up colors or cause a crash). It is useful for testing
and for some workarounds.  n may be a decimal number,
or 0x hex.  Run 
.IR xdpyinfo (1)
for the values.  One may
also use "TrueColor", etc. see <X11/X.h> for a list.
If the string ends in ":m" the for better or for
worse the visual depth is forced to be m.
.PP
\fB-overlay\fR
.IP
Handle multiple depth visuals on one screen, e.g. 8+24
and 24+8 overlay visuals (the 32 bits per pixel are
packed with 8 for PseudoColor and 24 for TrueColor).
.IP
Currently \fB-overlay\fR only works on Solaris via
.IR XReadScreen (3X11)
and IRIX using 
.IR XReadDisplay (3).
On Solaris there is a problem with image "bleeding"
around transient popup menus (but not for the menu
itself): a workaround is to disable SaveUnders
by passing the "\fB-su\fR" argument to Xsun (in
/etc/dt/config/Xservers).  Also note that the mouse
cursor shape is exactly correct in this mode.
.IP
Use \fB-overlay\fR as a workaround for situations like these:
Some legacy applications require the default visual to
be 8bpp (8+24), or they will use 8bpp PseudoColor even
when the default visual is depth 24 TrueColor (24+8).
In these cases colors in some windows will be messed
up in x11vnc unless \fB-overlay\fR is used.  Another use of
\fB-overlay\fR is to enable showing the exact mouse cursor
shape (details below).
.IP
Under \fB-overlay,\fR performance will be somewhat degraded
due to the extra image transformations required.
For optimal performance do not use \fB-overlay,\fR but rather
configure the X server so that the default visual is
depth 24 TrueColor and try to have all apps use that
visual (e.g. some apps have \fB-use24\fR or \fB-visual\fR options).
.PP
\fB-overlay_nocursor\fR
.IP
Sets \fB-overlay,\fR but does not try to draw the exact mouse
cursor shape using the overlay mechanism.
.PP
\fB-scale\fR \fIfraction\fR
.IP
Scale the framebuffer by factor \fIfraction\fR.  Values
less than 1 shrink the fb, larger ones expand it.
Note: image may not be sharp and response may be
slower.  Currently the cursor shape is not scaled.
If \fIfraction\fR contains a decimal point "." it
is taken as a floating point number, alternatively
the notation "m/n" may be used to denote fractions
exactly, e.g. \fB-scale\fR 2/3.
.IP
Scaling Options: can be added after \fIfraction\fR via
":", to supply multiple ":" options use commas.
If you just want a quick, rough scaling without
blending, append ":nb" to \fIfraction\fR (e.g. \fB-scale\fR
1/3:nb).  For compatibility with vncviewers the scaled
width is adjusted to be a multiple of 4: to disable
this use ":n4".  More esoteric options: ":in" use
interpolation scheme even when shrinking, ":pad",
pad scaled width and height to be multiples of scaling
denominator (e.g. 3 for 2/3).
.PP
\fB-viewonly\fR
.IP
All VNC clients can only watch (default off).
.PP
\fB-shared\fR
.IP
VNC display is shared (default off).
.PP
\fB-once\fR
.IP
Exit after the first successfully connected viewer
disconnects, opposite of \fB-forever.\fR This is the Default.
.PP
\fB-forever\fR
.IP
Keep listening for more connections rather than exiting
as soon as the first client(s) disconnect. Same as \fB-many\fR
.PP
\fB-timeout\fR \fIn\fR
.IP
Exit unless a client connects within the first n seconds
of startup.
.PP
\fB-inetd\fR
.IP
Launched by 
.IR inetd (1):
stdio instead of listening socket.
Note: if you are not redirecting stderr to a log file
(via shell 2> or \fB-o\fR option) you must also specify the
\fB-q\fR option, otherwise the stderr goes to the viewer.
.PP
\fB-connect\fR \fIstring\fR
.IP
For use with "vncviewer -listen" reverse connections.
If \fIstring\fR has the form "host" or "host:port"
the connection is made once at startup.  Use commas
for a list of host's and host:port's.
.IP
If \fIstring\fR contains "/" it is instead interpreted
as a file to periodically check for new hosts.
The first line is read and then the file is truncated.
Be careful for this usage mode if x11vnc is running as
root (e.g. via 
.IR inetd (1)
or 
.IR gdm (1)
).
.PP
\fB-vncconnect,\fR \fB-novncconnect\fR
.IP
Monitor the VNC_CONNECT X property set by the standard
VNC program 
.IR vncconnect (1).
When the property is
set to "host" or "host:port" establish a reverse
connection.  Using 
.IR xprop (1)
instead of vncconnect may
work (see the FAQ).  Default: \fB-vncconnect\fR
.PP
\fB-allow\fR \fIhost1[,host2..]\fR
.IP
Only allow client connections from hosts matching
the comma separated list of hostnames or IP addresses.
Can also be a numerical IP prefix, e.g. "192.168.100."
to match a simple subnet, for more control build
libvncserver with libwrap support (See the FAQ).  If the
list contains a "/" it instead is a interpreted as a
file containing addresses or prefixes that is re-read
each time a new client connects.  Lines can be commented
out with the "#" character in the usual way.
.PP
\fB-localhost\fR
.IP
Same as \fB-allow\fR 127.0.0.1
.PP
\fB-input\fR \fIstring\fR
.IP
Fine tuning of allowed user input.  If \fIstring\fR does
not contain a comma "," the tuning applies only to
normal clients.  Otherwise the part before "," is
for normal clients and the part after for view-only
clients.  "K" is for Keystroke input, "M" for
Mouse-motion input, and "B" for Button-click input.
Their presence in the string enables that type of input.
E.g. "\fB-input\fR \fIM\fR" means normal users can only move
the mouse and  "\fB-input\fR \fIKMB,M\fR" lets normal users do
anything and enables view-only users to move the mouse.
This option is ignored when a global \fB-viewonly\fR is in
effect (all input is discarded).
.PP
\fB-viewpasswd\fR \fIstring\fR
.IP
Supply a 2nd password for view-only logins.  The \fB-passwd\fR
(full-access) password must also be supplied.
.PP
\fB-passwdfile\fR \fIfilename\fR
.IP
Specify libvncserver \fB-passwd\fR via the first line of the
file \fIfilename\fR instead of via command line (where
others might see it via 
.IR ps (1)
).  If a second non blank
line exists in the file it is taken as a view-only
password (i.e. \fB-viewpasswd)\fR To supply an empty password
for either field the string "__EMPTY__" may be used.
Note: \fB-passwdfile\fR is a simple plaintext passwd, see
also \fB-rfbauth\fR and \fB-storepasswd\fR below for obfuscated
VNC password files.  Neither file should be readable
by others.
.PP
\fB-storepasswd\fR \fIpass\fR \fIfile\fR
.IP
Store password \fIpass\fR as the VNC password in the
file \fIfile\fR.  Once the password is stored the
program exits.  Use the password via "\fB-rfbauth\fR \fIfile\fR"
.PP
\fB-accept\fR \fIstring\fR
.IP
Run a command (possibly to prompt the user at the
X11 display) to decide whether an incoming client
should be allowed to connect or not.  \fIstring\fR is
an external command run via 
.IR system (3)
or some special
cases described below.  Be sure to quote \fIstring\fR
if it contains spaces, shell characters, etc.  If the
external command returns 0 the client is accepted,
otherwise the client is rejected.  See below for an
extension to accept a client view-only.
.IP
If x11vnc is running as root (say from 
.IR inetd (1)
or from
display managers 
.IR xdm (1)
, 
.IR gdm (1)
, etc), think about the
security implications carefully before supplying this
option (likewise for the \fB-gone\fR option).
.IP
Environment: The RFB_CLIENT_IP environment variable will
be set to the incoming client IP number and the port
in RFB_CLIENT_PORT (or -1 if unavailable).  Similarly,
RFB_SERVER_IP and RFB_SERVER_PORT (the x11vnc side
of the connection), are set to allow identification
of the tcp virtual circuit.  The x11vnc process
id will be in RFB_X11VNC_PID, a client id number in
RFB_CLIENT_ID, and the number of other connected clients
in RFB_CLIENT_COUNT.  RFB_MODE will be "accept"
.IP
If \fIstring\fR is "popup" then a builtin popup window
is used.  The popup will time out after 120 seconds,
use "popup:N" to modify the timeout to N seconds
(use 0 for no timeout)
.IP
If \fIstring\fR is "xmessage" then an 
.IR xmessage (1)
invocation is used for the command.  xmessage must be
installed on the machine for this to work.
.IP
Both "popup" and "xmessage" will present an option
for accepting the client "View-Only" (the client
can only watch).  This option will not be presented if
\fB-viewonly\fR has been specified, in which case the entire
display is view only.
.IP
If the user supplied command is prefixed with something
like "yes:0,no:*,view:3 mycommand ..." then this
associates the numerical command return code with
the actions: accept, reject, and accept-view-only,
respectively.  Use "*" instead of a number to indicate
the default action (in case the command returns an
unexpected value).  E.g. "no:*" is a good choice.
.IP
Note that x11vnc blocks while the external command
or popup is running (other clients may see no updates
during this period).
.IP
More \fB-accept\fR tricks: use "popupmouse" to only allow
mouse clicks in the builtin popup to be recognized.
Similarly use "popupkey" to only recognize
keystroke responses.  These are to help avoid the
user accidentally accepting a client by typing or
clicking. All 3 of the popup keywords can be followed
by +N+M to supply a position for the popup window.
The default is to center the popup window.
.PP
\fB-gone\fR \fIstring\fR
.IP
As \fB-accept,\fR except to run a user supplied command when
a client goes away (disconnects).  RFB_MODE will be
set to "gone" and the other RFB_* variables are as
in \fB-accept.\fR  Unlike \fB-accept,\fR the command return code
is not interpreted by x11vnc.  Example: \fB-gone\fR 'xlock &'
.PP
\fB-users\fR \fIlist\fR
.IP
If x11vnc is started as root (say from 
.IR inetd (1)
or from
display managers 
.IR xdm (1)
, 
.IR gdm (1)
, etc), then as soon
as possible after connections to the X display are
established try to switch to one of the users in the
comma separated \fIlist\fR.  If x11vnc is not running as
root this option is ignored.
.IP
Why use this option?  In general it is not needed since
x11vnc is already connected to the X display and can
perform its primary functions.  The option was added
to make some of the *external* utility commands x11vnc
occasionally runs work properly.  In particular under
GNOME and KDE to implement the "\fB-solid\fR \fIcolor\fR" feature
external commands (gconftool-2 and dcop) must be run
as the user owning the desktop session.  Since this
option switches userid it also affects the userid used
to run the processes for the \fB-accept\fR and \fB-gone\fR options.
It also affects the ability to read files for options
such as \fB-connect,\fR \fB-allow,\fR and \fB-remap.\fR  Note that the
\fB-connect\fR file is also sometimes written to.
.IP
So be careful with this option since in many situations
its use can decrease security.
.IP
The switch to a user will only take place if the
display can still be successfully opened as that user
(this is primarily to try to guess the actual owner
of the session). Example: "\fB-users\fR \fIfred,wilma,betty\fR".
Note that a malicious user "barney" by quickly using
"xhost +" when logging in may get x11vnc to switch
to user "fred".  What happens next?
.IP
Under display managers it may be a long time before
the switch succeeds (i.e. a user logs in).  To make
it switch immediately regardless if the display
can be reopened prefix the username with the "+"
character. E.g. "\fB-users\fR \fI+bob\fR" or "\fB-users\fR \fI+nobody\fR".
The latter (i.e. switching immediately to user
"nobody") is probably the only use of this option
that increases security.
.IP
To immediately switch to a user *before* connections
to the X display are made or any files opened use the
"=" character: "\fB-users\fR \fI=bob\fR".  That user needs to
be able to open the X display of course.
.IP
The special user "guess=" means to examine the utmpx
database (see 
.IR who (1)
) looking for a user attached to
the display number (from DISPLAY or \fB-display\fR option)
and try him/her.  To limit the list of guesses, use:
"\fB-users\fR \fIguess=bob,betty\fR".
.IP
Even more sinister is the special user "lurk=" that
means to try to guess the DISPLAY from the utmpx login
database as well.  So it "lurks" waiting for anyone
to log into an X session and then connects to it.
Specify a list of users after the = to limit which
users will be tried.  To enable a difference searching
mode, if the first user in the list is something like
":0" or ":0-2" that indicates a range of DISPLAY
numbers that will be tried (regardless of whether
they are in the utmpx database) for all users that
are logged in.  Examples: "\fB-users\fR \fIlurk=\fR" and also
"\fB-users\fR \fIlurk=:0-1,bob,mary\fR"
.IP
Be especially careful using the "guess=" and "lurk="
modes.  They are not recommended for use on machines
with untrustworthy local users.
.PP
\fB-noshm\fR
.IP
Do not use the MIT-SHM extension for the polling.
Remote displays can be polled this way: be careful this
can use large amounts of network bandwidth.  This is
also of use if the local machine has a limited number
of shm segments and \fB-onetile\fR is not sufficient.
.PP
\fB-flipbyteorder\fR
.IP
Sometimes needed if remotely polled host has different
endianness.  Ignored unless \fB-noshm\fR is set.
.PP
\fB-onetile\fR
.IP
Do not use the new copy_tiles() framebuffer mechanism,
just use 1 shm tile for polling.  Limits shm segments
used to 3.
.PP
\fB-solid\fR \fI[color]\fR
.IP
To improve performance, when VNC clients are connected
try to change the desktop background to a solid color.
The [color] is optional: the default color is "cyan4".
For a different one specify the X color (rgb.txt name,
e.g. "darkblue" or numerical "#RRGGBB").
.IP
Currently this option only works on GNOME, KDE, CDE,
and classic X (i.e. with the background image on the
root window).  The "gconftool-2" and "dcop" external
commands are run for GNOME and KDE respectively.
Other desktops won't work, e.g. Xfce (send us the
corresponding commands if you find them).  If x11vnc is
running as root (
.IR inetd (1)
or 
.IR gdm (1)
), the \fB-users\fR option
may be needed for GNOME and KDE.  If x11vnc guesses
your desktop incorrectly, you can force it by prefixing
color with "gnome:", "kde:", "cde:" or "root:".
.PP
\fB-blackout\fR \fIstring\fR
.IP
Black out rectangles on the screen. \fIstring\fR is a
comma separated list of WxH+X+Y type geometries for
each rectangle.
.PP
\fB-xinerama\fR
.IP
If your screen is composed of multiple monitors
glued together via XINERAMA, and that screen is
non-rectangular this option will try to guess the
areas to black out (if your system has libXinerama).
.IP
In general on XINERAMA displays you may need to use the
\fB-xwarppointer\fR option if the mouse pointer misbehaves.
.PP
\fB-xrandr\fR \fI[mode]\fR
.IP
If the display supports the XRANDR (X Resize, Rotate
and Reflection) extension, and you expect XRANDR events
to occur to the display while x11vnc is running, this
options indicates x11vnc should try to respond to
them (as opposed to simply crashing by assuming the
old screen size).  See the 
.IR xrandr (1)
manpage and run
\'xrandr \fB-q'\fR for more info.  [mode] is optional and
described below.
.IP
Since watching for XRANDR events and trapping errors
increases polling overhead, only use this option if
XRANDR changes are expected.  For example on a rotatable
screen PDA or laptop, or using a XRANDR-aware Desktop
where you resize often.  It is best to be viewing with a
vncviewer that supports the NewFBSize encoding, since it
knows how to react to screen size changes.  Otherwise,
libvncserver tries to do so something reasonable for
viewers that cannot do this (portions of the screen
may be clipped, unused, etc).
.IP
"mode" defaults to "resize", which means create a
new, resized, framebuffer and hope all viewers can cope
with the change.  "newfbsize" means first disconnect
all viewers that do not support the NewFBSize VNC
encoding, and then resize the framebuffer.  "exit"
means disconnect all viewer clients, and then terminate
x11vnc.
.PP
\fB-padgeom\fR \fIWxH\fR
.IP
Whenever a new vncviewer connects, the framebuffer is
replaced with a fake, solid black one of geometry WxH.
Shortly afterwards the framebuffer is replaced with the
real one.  This is intended for use with vncviewers
that do not support NewFBSize and one wants to make
sure the initial viewer geometry will be big enough
to handle all subsequent resizes (e.g. under \fB-xrandr,\fR
\fB-remote\fR id:windowid, rescaling, etc.)
.PP
\fB-o\fR \fIlogfile\fR
.IP
Write stderr messages to file \fIlogfile\fR instead of
to the terminal.  Same as "\fB-logfile\fR \fIfile\fR".  To append
to the file use "\fB-oa\fR \fIfile\fR" or "\fB-logappend\fR \fIfile\fR".
.PP
\fB-rc\fR \fIfilename\fR
.IP
Use \fIfilename\fR instead of $HOME/.x11vncrc for rc file.
.PP
\fB-norc\fR
.IP
Do not process any .x11vncrc file for options.
.PP
\fB-h,\fR \fB-help\fR
.IP
Print this help text.
-?, \fB-opts\fR              Only list the x11vnc options.
.PP
\fB-V,\fR \fB-version\fR
.IP
Print program version and last modification date.
.PP
\fB-q\fR
.IP
Be quiet by printing less informational output to
stderr.  Same as \fB-quiet.\fR
.PP
\fB-bg\fR
.IP
Go into the background after screen setup.  Messages to
stderr are lost unless \fB-o\fR logfile is used.  Something
like this could be useful in a script:
.IP
port=`ssh $host "x11vnc -display :0 -bg" | grep PORT`
.IP
port=`echo "$port" | sed -e 's/PORT=//'`
.IP
port=`expr $port - 5900`
.IP
vncviewer $host:$port
.PP
\fB-modtweak,\fR \fB-nomodtweak\fR
.IP
Option \fB-modtweak\fR automatically tries to adjust the AltGr
and Shift modifiers for differing language keyboards
between client and host.  Otherwise, only a single key
press/release of a Keycode is simulated (i.e. ignoring
the state of the modifiers: this usually works for
identical keyboards).  Also useful in resolving cases
where a Keysym is bound to multiple keys (e.g. "<" + ">"
and "," + "<" keys).  Default: \fB-modtweak\fR
.PP
\fB-xkb\fR
.IP
When in modtweak mode, use the XKEYBOARD extension (if
the X display supports it) to do the modifier tweaking.
This is powerful and should be tried if there are still
keymapping problems when using \fB-modtweak\fR by itself.
.PP
\fB-skip_keycodes\fR \fIstring\fR
.IP
Ignore the comma separated list of decimal keycodes.
Perhaps these are keycodes not on your keyboard but
your X server thinks exist.  Currently only applies
to \fB-xkb\fR mode.  Use this option to help x11vnc in the
reverse problem it tries to solve: Keysym -> Keycode(s)
when ambiguities exist (more than one Keycode per
Keysym).  Run 'xmodmap \fB-pk'\fR to see your keymapping.
Example: "\fB-skip_keycodes\fR \fI94,114\fR"
.PP
\fB-add_keysyms\fR
.IP
If a Keysym is received from a VNC viewer and
that Keysym does not exist in the X server, then
add the Keysym to the X server's keyboard mapping.
Added Keysyms will be removed when x11vnc exits.
.PP
\fB-clear_mods\fR
.IP
At startup and exit clear the modifier keys by sending
KeyRelease for each one. The Lock modifiers are skipped.
Used to clear the state if the display was accidentally
left with any pressed down.
.PP
\fB-clear_keys\fR
.IP
As \fB-clear_mods,\fR except try to release any pressed key.
Note that this option and \fB-clear_mods\fR can interfere
with a person typing at the physical keyboard.
.PP
\fB-remap\fR \fIstring\fR
.IP
Read Keysym remappings from file named \fIstring\fR.
Format is one pair of Keysyms per line (can be name
or hex value) separated by a space.  If no file named
\fIstring\fR exists, it is instead interpreted as this
form: key1-key2,key3-key4,...  See <X11/keysymdef.h>
header file for a list of Keysym names, or use 
.IR xev (1).
To map a key to a button click, use the fake Keysyms
"Button1", ..., etc. E.g: "\fB-remap\fR \fISuper_R-Button2\fR"
(useful for pasting on a laptop)
.PP
\fB-norepeat,\fR \fB-repeat\fR
.IP
Option \fB-norepeat\fR disables X server key auto repeat
when VNC clients are connected.  This works around a
repeating keystrokes bug (triggered by long processing
delays between key down and key up client events:
either from large screen changes or high latency).
Note: your VNC viewer side will likely do autorepeating,
so this is no loss unless someone is simultaneously at
the real X display.  Default: \fB-norepeat\fR
.PP
\fB-nofb\fR
.IP
Ignore video framebuffer: only process keyboard and
pointer.  Intended for use with Win2VNC and x2vnc
dual-monitor setups.
.PP
\fB-nobell\fR
.IP
Do not watch for XBell events. (no beeps will be heard)
Note: XBell monitoring requires the XKEYBOARD extension.
.PP
\fB-nosel\fR
.IP
Do not manage exchange of X selection/cutbuffer between
VNC viewers and the X server.
.PP
\fB-noprimary\fR
.IP
Do not poll the PRIMARY selection for changes to send
back to clients.  (PRIMARY is still set on received
changes, however).
.PP
\fB-cursor\fR \fI[mode],\fR \fB-nocursor\fR
.IP
Sets how the pointer cursor shape (little icon at the
mouse pointer) should be handled.  The "mode" string
is optional and is described below.  The default
is to show some sort of cursor shape(s).  How this
is done depends on the VNC viewer and the X server.
Use \fB-nocursor\fR to disable cursor shapes completely.
.IP
Some VNC viewers support the TightVNC CursorPosUpdates
and CursorShapeUpdates extensions (cuts down on
network traffic by not having to send the cursor image
every time the pointer is moved), in which case these
extensions are used (see \fB-nocursorshape\fR and \fB-nocursorpos\fR
below to disable).  For other viewers the cursor shape
is written directly to the framebuffer every time the
pointer is moved or changed and gets sent along with
the other framebuffer updates.  In this case, there
will be some lag between the vnc viewer pointer and
the remote cursor position.
.IP
If the X display supports retrieving the cursor shape
information from the X server, then the default is
to use that mode.  On Solaris this can be done with
the SUN_OVL extension using \fB-overlay\fR (see also the
\fB-overlay_nomouse\fR option).  A similar overlay scheme
is used on IRIX.  Xorg (e.g. Linux) and recent Solaris
Xsun servers support the XFIXES extension to retrieve
the exact cursor shape from the X server.  If XFIXES
is present it is preferred over Overlay and is used by
default (see \fB-noxfixes\fR below).  This can be disabled
with \fB-nocursor,\fR and also some values of the "mode"
option below.
.IP
Note that under XFIXES cursors with transparency (alpha
channel) will not be exactly represented and one may
find Overlay preferable.  See also the \fB-alphacut\fR and
\fB-alphafrac\fR options below as fudge factors to try to
improve the situation for cursors with transparency
for a given theme.
.IP
The "mode" string can be used to fine-tune the
displaying of cursor shapes.  It can be used the
following ways:
.IP
"\fB-cursor\fR \fIarrow\fR" - just show the standard arrow
nothing more or nothing less.
.IP
"\fB-cursor\fR \fInone\fR" - same as "\fB-nocursor\fR"
.IP
"\fB-cursor\fR \fIX\fR" - when the cursor appears to be on the
root window, draw the familiar X shape.  Some desktops
such as GNOME cover up the root window completely,
and so this will not work, try "X1", etc, to try to
shift the tree depth.  On high latency links or slow
machines there will be a time lag between expected and
the actual cursor shape.
.IP
"\fB-cursor\fR \fIsome\fR" - like "X" but use additional
heuristics to try to guess if the window should have
a windowmanager-like resizer cursor or a text input
I-beam cursor.  This is a complete hack, but may be
useful in some situations because it provides a little
more feedback about the cursor shape.
.IP
"\fB-cursor\fR \fImost\fR" - try to show as many cursors as
possible.  Often this will only be the same as "some"
unless the display has overlay visuals or XFIXES
extensions available.  On Solaris and IRIX if XFIXES
is not available, \fB-overlay\fR mode will be attempted.
.PP
\fB-noxfixes\fR
.IP
Do not use the XFIXES extension to draw the exact cursor
shape even if it is available.
.PP
\fB-alphacut\fR \fIn\fR
.IP
When using the XFIXES extension for the cursor shape,
cursors with transparency will not be displayed exactly
(but opaque ones will).  This option sets n as a cutoff
for cursors that have transparency ("alpha channel"
with values ranging from 0 to 255) Any cursor pixel with
alpha value less than n becomes completely transparent.
Otherwise the pixel is completely opaque.  Default 240
.IP
Note: the options \fB-alphacut,\fR \fB-alphafrac,\fR and \fB-alphafrac\fR
may be removed if a more accurate internal method for
handling cursor transparency is implemented.
.PP
\fB-alphafrac\fR \fIfraction\fR
.IP
With the threshold in \fB-alphacut\fR some cursors will become
almost completely transparent because their alpha values
are not high enough.  For those cursors adjust the
alpha threshold until fraction of the non-zero alpha
channel pixels become opaque.  Default 0.33
.PP
\fB-alpharemove\fR
.IP
By default, XFIXES cursors pixels with transparency have
the alpha factor multiplied into the RGB color values
(i.e. that corresponding to blending the cursor with a
black background).  Specify this option to remove the
alpha factor. (useful for light colored semi-transparent
cursors).
.PP
\fB-noalphablend\fR
.IP
In XFIXES mode do not send cursor alpha channel data
to libvncserver.  The default is to send it.  The
alphablend effect will only be visible in \fB-nocursorshape\fR
mode or for clients with cursorshapeupdates turned
off. (However there is a hack for 32bpp with depth 24,
it uses the extra 8 bits to store cursor transparency
for use with a hacked vncviewer that applies the
transparency locally.  See the FAQ for more info).
.PP
\fB-nocursorshape\fR
.IP
Do not use the TightVNC CursorShapeUpdates extension
even if clients support it.  See \fB-cursor\fR above.
.PP
\fB-cursorpos,\fR \fB-nocursorpos\fR
.IP
Option \fB-cursorpos\fR enables sending the X cursor position
back to all vnc clients that support the TightVNC
CursorPosUpdates extension.  Other clients will be able
to see the pointer motions. Default: \fB-cursorpos\fR
.PP
\fB-xwarppointer\fR
.IP
Move the pointer with 
.IR XWarpPointer (3X)
instead of
the XTEST extension.  Use this as a workaround
if the pointer motion behaves incorrectly, e.g.
on touchscreens or other non-standard setups.
Also sometimes needed on XINERAMA displays.
.PP
\fB-buttonmap\fR \fIstring\fR
.IP
String to remap mouse buttons.  Format: IJK-LMN, this
maps buttons I -> L, etc., e.g.  \fB-buttonmap\fR 13-31
.IP
Button presses can also be mapped to keystrokes: replace
a button digit on the right of the dash with :<sym>:
or :<sym1>+<sym2>: etc. for multiple keys. For example,
if the viewing machine has a mouse-wheel (buttons 4 5)
but the x11vnc side does not, these will do scrolls:
.IP
\fB-buttonmap\fR 12345-123:Prior::Next:
.IP
\fB-buttonmap\fR 12345-123:Up+Up+Up::Down+Down+Down:
.IP
See <X11/keysymdef.h> header file for a list of Keysyms,
or use the 
.IR xev (1)
program.  Note: mapping of button
clicks to Keysyms may not work if \fB-modtweak\fR or \fB-xkb\fR is
needed for the Keysym.
.IP
If you include a modifier like "Shift_L" the
modifier's up/down state is toggled, e.g. to send
"The" use :Shift_L+t+Shift_L+h+e: (the 1st one is
shift down and the 2nd one is shift up). (note: the
initial state of the modifier is ignored and not reset)
To include button events use "Button1", ... etc.
.PP
\fB-nodragging\fR
.IP
Do not update the display during mouse dragging events
(mouse button held down).  Greatly improves response on
slow setups, but you lose all visual feedback for drags,
text selection, and some menu traversals.  It overrides
any \fB-pointer_mode\fR setting
.PP
\fB-pointer_mode\fR \fIn\fR
.IP
Various pointer motion update schemes. "\fB-pm\fR" is
an alias.  The problem is pointer motion can cause
rapid changes on the screen: consider the rapid changes
when you drag a large window around.  Neither x11vnc's
screen polling and vnc compression routines nor the
bandwidth to the vncviewers can keep up these rapid
screen changes: everything will bog down when dragging
or scrolling.  So a scheme has to be used to "eat"
much of that pointer input before re-polling the screen
and sending out framebuffer updates. The mode number
\fIn\fR can be 0 to 4 and selects one of the schemes
desribed below.
.IP
n=0: does the same as \fB-nodragging.\fR (all screen polling
is suspended if a mouse button is pressed.)
.IP
n=1: was the original scheme used to about Jan 2004:
it basically just skips \fB-input_skip\fR keyboard or pointer
events before repolling the screen.
.IP
n=2 is an improved scheme: by watching the current rate
of input events it tries to detect if it should try to
"eat" additional pointer events before continuing.
.IP
n=3 is basically a dynamic \fB-nodragging\fR mode: it detects
when the mouse motion has paused and then refreshes
the display.
.IP
n=4: attempts to measures network rates and latency,
the video card read rate, and how many tiles have been
changed on the screen.  From this, it aggressively tries
to push screen "frames" when it decides it has enough
resources to do so.  NOT FINISHED.
.IP
The default n is 2. Note that modes 2, 3, 4 will skip
\fB-input_skip\fR keyboard events (but it will not count
pointer events).  Also note that these modes are not
available in \fB-threads\fR mode which has its own pointer
event handling mechanism.
.IP
To try out the different pointer modes to see which
one gives the best response for your usage, it is
convenient to use the remote control function, for
example "x11vnc \fB-R\fR pm:4" or the tcl/tk gui (Tuning ->
pointer_mode -> n).
.PP
\fB-input_skip\fR \fIn\fR
.IP
For the pointer handling when non-threaded: try to
read n user input events before scanning display. n < 0
means to act as though there is always user input.
Default: 10
.PP
\fB-speeds\fR \fIrd,bw,lat\fR
.IP
x11vnc tries to estimate some speed parameters that
are used to optimize scheduling (e.g. \fB-pointer_mode\fR
4) and other things.  Use the \fB-speeds\fR option to set
these manually.  The triple \fIrd,bw,lat\fR corresponds
to video h/w read rate in MB/sec, network bandwidth to
clients in KB/sec, and network latency to clients in
milliseconds, respectively.  If a value is left blank,
e.g. "\fB-speeds\fR \fI,100,15\fR", then the internal scheme is
used to estimate the empty value(s).
.IP
Typical PC video cards have read rates of 5-10 MB/sec.
If the framebuffer is in main memory instead of video
h/w (e.g. SunRay, shadowfb, Xvfb), the read rate may
be much faster.  "x11perf \fB-getimage500"\fR can be used
to get a lower bound (remember to factor in the bytes
per pixel).  It is up to you to estimate the network
bandwith to clients.  For the latency the 
.IR ping (1)
command can be used.
.IP
For convenience there are some aliases provided,
e.g. "\fB-speeds\fR \fImodem\fR".  The aliases are: "modem" for
6,4,200; "dsl" for 6,100,50; and "lan" for 6,5000,1
.PP
\fB-debug_pointer\fR
.IP
Print debugging output for every pointer event.
.PP
\fB-debug_keyboard\fR
.IP
Print debugging output for every keyboard event.
.PP
Same as \fB-dp\fR and \fB-dk,\fR respectively.  Use multiple
times for more output.
.PP
\fB-defer\fR \fItime\fR
.IP
Time in ms to wait for updates before sending to client
(deferUpdateTime)  Default: 30
.PP
\fB-wait\fR \fItime\fR
.IP
Time in ms to pause between screen polls.  Used to cut
down on load.  Default: 30
.PP
\fB-nap\fR
.IP
Monitor activity and if it is low take longer naps
.PP
\fB-nonap\fR
.IP
between screen polls to really cut down load when idle.
Default: take naps
.PP
\fB-sb\fR \fItime\fR
.IP
Time in seconds after NO activity (e.g. screen blank)
to really throttle down the screen polls (i.e. sleep
for about 1.5 secs). Use 0 to disable.  Default: 60
.PP
\fB-sigpipe\fR \fIstring\fR
.IP
Broken pipe (SIGPIPE) handling.  \fIstring\fR can be
"ignore" or "exit".  For "ignore" libvncserver
will handle the abrupt loss of a client and continue,
for "exit" x11vnc will cleanup and exit at the 1st
broken connection.  Default: "ignore".
.PP
\fB-threads,\fR \fB-nothreads\fR
.IP
Whether or not to use the threaded libvncserver
algorithm [rfbRunEventLoop] if libpthread is available
Default: \fB-nothreads\fR
.PP
\fB-fs\fR \fIf\fR
.IP
If the fraction of changed tiles in a poll is greater
than f, the whole screen is updated.  Default: 0.75
.PP
\fB-gaps\fR \fIn\fR
.IP
Heuristic to fill in gaps in rows or cols of n or
less tiles.  Used to improve text paging.  Default: 4
.PP
\fB-grow\fR \fIn\fR
.IP
Heuristic to grow islands of changed tiles n or wider
by checking the tile near the boundary.  Default: 3
.PP
\fB-fuzz\fR \fIn\fR
.IP
Tolerance in pixels to mark a tiles edges as changed.
Default: 2
.PP
\fB-snapfb\fR
.IP
Instead of polling the X display framebuffer (fb) for
changes, periodically copy all of X display fb into main
memory and examine that copy for changes.  Under some
circumstances this will improve interactive response,
or at least make things look smoother, but in others
(many) it will make the response worse.  If the video
h/w fb is such that reading small tiles is very slow
this mode could help.  To keep the "framerate" up
the screen size x bpp cannot be too large.  Note that
this mode is very wasteful of memory I/O resources
(it makes full screen copies even if nothing changes).
It may be of use in video capture-like applications,
or where window tearing is a problem.
.PP
\fB-gui\fR \fI[gui-opts]\fR
.IP
Start up a simple tcl/tk gui based on the the remote
control options \fB-remote/-query\fR described below.
Requires the "wish" program to be installed on the
machine.  "gui-opts" is not required: the default is
to start up both the gui and x11vnc with the gui showing
up on the X display in the environment variable DISPLAY.
.IP
"gui-opts" can be a comma separated list of items.
Currently there are these types of items: 1) a gui mode,
a 2) gui "simplicity", and 3) the X display the gui
should display on.
.IP
1) The gui mode can be "start", "conn", or "wait"
"start" is the default mode above and is not required.
"conn" means do not automatically start up x11vnc,
but instead just try to connect to an existing x11vnc
process.  "wait" means just start the gui and nothing
else (you will later instruct the gui to start x11vnc
or connect to an existing one.)
.IP
2) The gui simplicity is off by default (a power-user
gui with all options is presented) To start with
something less daunting supply the string "simple"
("ez" is an alias for this).  Once the gui is
started you can toggle between the two with "Misc ->
simple_gui".
.IP
3) Note the possible confusion regarding the potentially
two different X displays: x11vnc polls one, but you
may want the gui to appear on another.  For example, if
you ssh in and x11vnc is not running yet you may want
the gui to come back to you via your ssh redirected X
display (e.g. localhost:10).
.IP
Examples: "x11vnc \fB-gui",\fR "x11vnc \fB-gui\fR ez"
"x11vnc \fB-gui\fR localhost:10", "x11vnc \fB-gui\fR conn,host:0"
.IP
If you do not specify a gui X display in "gui-opts"
then the DISPLAY environment variable and \fB-display\fR
option are tried (in that order).  Regarding the x11vnc
X display the gui will try to connect to, it first
tries \fB-display\fR and then DISPLAY.  For example, "x11vnc
\fB-display\fR :0 \fB-gui\fR otherhost:0", will remote control an
x11vnc polling :0 and display the gui on otherhost:0
.IP
If you do not intend to start x11vnc from the gui
(i.e. just remote control an existing one), then the
gui process can run on a different machine from the
x11vnc server as long as X permissions, etc. permit
communication between the two.
.PP
\fB-remote\fR \fIcommand\fR
.IP
Remotely control some aspects of an already running
x11vnc server.  "\fB-R\fR" and "\fB-r\fR" are aliases for
"\fB-remote\fR".  After the remote control command is
sent to the running server the 'x11vnc \fB-remote\fR ...'
command exits.  You can often use the \fB-query\fR command
(see below) to see if the x11vnc server processed your
\fB-remote\fR command.
.IP
The default communication channel is that of X
properties (specifically VNC_CONNECT), and so this
command must be run with correct settings for DISPLAY
and possibly XAUTHORITY to connect to the X server
and set the property.  Alternatively, use the \fB-display\fR
and \fB-auth\fR options to set them to the correct values.
The running server cannot use the \fB-novncconnect\fR option
because that disables the communication channel.
See below for alternate channels.
.IP
For example: 'x11vnc \fB-remote\fR stop' (which is the same as
\'x11vnc \fB-R\fR stop') will close down the x11vnc server.
\'x11vnc \fB-R\fR shared' will enable shared connections, and
\'x11vnc \fB-R\fR scale:3/4' will rescale the desktop.
.IP
Note: the more drastic the change induced by the \fB-remote\fR
command, the bigger the chance for bugs or crashes.
Please report reproducible bugs.
.IP
.IP
The following \fB-remote/-R\fR commands are supported:
.IP
stop            terminate the server, same as "quit"
                "exit" or "shutdown".
.IP
ping            see if the x11vnc server responds.
                Return is: ans=ping:<xdisplay>
.IP
blacken         try to push a black fb update to all
                clients (due to timings a client
                could miss it). Same as "zero", also
                "zero:x1,y1,x2,y2" for a rectangle.
.IP
refresh         send the entire fb to all clients.
.IP
reset           recreate the fb, polling memory, etc.
.IP
id:windowid     set \fB-id\fR window to "windowid". empty
                or "root" to go back to root window
.IP
sid:windowid    set \fB-sid\fR window to "windowid"
.IP
flashcmap       enable  \fB-flashcmap\fR mode.
.IP
noflashcmap     disable \fB-flashcmap\fR mode.
.IP
notruecolor     enable  \fB-notruecolor\fR mode.
.IP
truecolor       disable \fB-notruecolor\fR mode.
.IP
overlay         enable  \fB-overlay\fR mode (if applicable).
.IP
nooverlay       disable \fB-overlay\fR mode.
.IP
overlay_cursor  in \fB-overlay\fR mode, enable cursor drawing.
.IP
overlay_nocursor disable cursor drawing. same as
                nooverlay_cursor.
.IP
visual:vis      set \fB-visual\fR to "vis"
.IP
scale:frac      set \fB-scale\fR to "frac"
.IP
viewonly        enable  \fB-viewonly\fR mode.
.IP
noviewonly      disable \fB-viewonly\fR mode.
.IP
shared          enable  \fB-shared\fR mode.
.IP
noshared        disable \fB-shared\fR mode.
.IP
forever         enable  \fB-forever\fR mode.
.IP
noforever       disable \fB-forever\fR mode.
.IP
timeout:n       reset \fB-timeout\fR to n, if there are
                currently no clients, exit unless one
                connects in the next n secs.
.IP
deny            deny any new connections, same as "lock"
.IP
nodeny          allow new connections, same as "unlock"
.IP
connect:host    do reverse connection to host, "host"
                may be a comma separated list of hosts
                or host:ports.  See \fB-connect.\fR
.IP
disconnect:host disconnect any clients from "host"
                same as "close:host".  Use host
                "all" to close all current clients.
                If you know the client internal hex ID,
                e.g. 0x3 (returned by \fB-query\fR clients and
                RFB_CLIENT_ID), you can use that too.
.IP
allowonce:host  For the next connection only, allow
                connection from "host".
.IP
allow:hostlist  set \fB-allow\fR list to (comma separated)
                "hostlist". See \fB-allow\fR and \fB-localhost.\fR
                Do not use with \fB-allow\fR /path/to/file
                Use "+host" to add a single host, and
                use "\fB-host\fR" to delete a single host
.IP
localhost       enable  \fB-localhost\fR mode
.IP
nolocalhost     disable \fB-localhost\fR mode
.IP
input:str       set \fB-input\fR to "str", empty to disable.
.IP
client_input:str set the K, M, B \fB-input\fR on a per-client
                basis.  select which client as for
                disconnect, e.g. client_input:host:MB
                or client_input:0x2:K
.IP
accept:cmd      set \fB-accept\fR "cmd" (empty to disable).
.IP
gone:cmd        set \fB-gone\fR "cmd" (empty to disable).
.IP
noshm           enable  \fB-noshm\fR mode.
.IP
shm             disable \fB-noshm\fR mode (i.e. use shm).
.IP
flipbyteorder   enable \fB-flipbyteorder\fR mode, you may need
                to set noshm for this to do something.
.IP
noflipbyteorder disable \fB-flipbyteorder\fR mode.
.IP
onetile         enable  \fB-onetile\fR mode. (you may need to
                set shm for this to do something)
.IP
noonetile       disable \fB-onetile\fR mode.
.IP
solid           enable  \fB-solid\fR mode
.IP
nosolid         disable \fB-solid\fR mode.
.IP
solid_color:color set \fB-solid\fR color (and apply it).
.IP
blackout:str    set \fB-blackout\fR "str" (empty to disable).
                See \fB-blackout\fR for the form of "str"
                (basically: WxH+X+Y,...)
                Use "+WxH+X+Y" to append a single
                rectangle use "-WxH+X+Y" to delete one
.IP
xinerama        enable  \fB-xinerama\fR mode. (if applicable)
.IP
noxinerama      disable \fB-xinerama\fR mode.
.IP
xrandr          enable  \fB-xrandr\fR mode. (if applicable)
.IP
noxrandr        disable \fB-xrandr\fR mode.
.IP
xrandr_mode:mode set the \fB-xrandr\fR mode to "mode".
.IP
padgeom:WxH     set \fB-padgeom\fR to WxH (empty to disable)
                If WxH is "force" or "do" the padded
                geometry fb is immediately applied.
.IP
quiet           enable  \fB-quiet\fR mode.
.IP
noquiet         disable \fB-quiet\fR mode.
.IP
modtweak        enable  \fB-modtweak\fR mode.
.IP
nomodtweak      enable  \fB-nomodtweak\fR mode.
.IP
xkb             enable  \fB-xkb\fR modtweak mode.
.IP
noxkb           disable \fB-xkb\fR modtweak mode.
.IP
skip_keycodes:str enable \fB-xkb\fR \fB-skip_keycodes\fR "str".
.IP
add_keysyms     enable \fB-add_keysyms\fR mode.
.IP
noadd_keysyms   stop adding keysyms. those added will
                still be removed at exit.
.IP
clear_mods      enable  \fB-clear_mods\fR mode and clear them.
.IP
noclear_mods    disable \fB-clear_mods\fR mode.
.IP
clear_keys      enable  \fB-clear_keys\fR mode and clear them.
.IP
noclear_keys    disable \fB-clear_keys\fR mode.
.IP
remap:str       set \fB-remap\fR "str" (empty to disable).
                See \fB-remap\fR for the form of "str"
                (basically: key1-key2,key3-key4,...)
                Use "+key1-key2" to append a single
                keymapping, use "-key1-key2" to delete.
.IP
norepeat        enable  \fB-norepeat\fR mode.
.IP
repeat          disable \fB-norepeat\fR mode.
.IP
nofb            enable  \fB-nofb\fR mode.
.IP
fb              disable \fB-nofb\fR mode.
.IP
bell            enable  bell (if supported).
.IP
nobell          disable bell.
.IP
nosel           enable  \fB-nosel\fR mode.
.IP
sel             disable \fB-nosel\fR mode.
.IP
noprimary       enable  \fB-noprimary\fR mode.
.IP
primary         disable \fB-noprimary\fR mode.
.IP
cursor:mode     enable  \fB-cursor\fR "mode".
.IP
show_cursor     enable  showing a cursor.
.IP
noshow_cursor   disable showing a cursor. (same as
                "nocursor")
.IP
xfixes          enable  xfixes cursor shape mode.
.IP
noxfixes        disable xfixes cursor shape mode.
.IP
alphacut:n      set \fB-alphacut\fR to n.
.IP
alphafrac:f     set \fB-alphafrac\fR to f.
.IP
alpharemove     enable  \fB-alpharemove\fR mode.
.IP
noalpharemove   disable \fB-alpharemove\fR mode.
.IP
alphablend      disable \fB-noalphablend\fR mode.
.IP
noalphablend    enable  \fB-noalphablend\fR mode.
.IP
cursorshape     disable \fB-nocursorshape\fR mode.
.IP
nocursorshape   enable  \fB-nocursorshape\fR mode.
.IP
cursorpos       disable \fB-nocursorpos\fR mode.
.IP
nocursorpos     enable  \fB-nocursorpos\fR mode.
.IP
xwarp           enable  \fB-xwarppointer\fR mode.
.IP
noxwarp         disable \fB-xwarppointer\fR mode.
.IP
buttonmap:str   set \fB-buttonmap\fR "str", empty to disable
.IP
dragging        disable \fB-nodragging\fR mode.
.IP
nodragging      enable  \fB-nodragging\fR mode.
.IP
pointer_mode:n  set \fB-pointer_mode\fR to n. same as "pm"
.IP
input_skip:n    set \fB-input_skip\fR to n.
.IP
speeds:str      set \fB-speeds\fR to str.
.IP
debug_pointer   enable  \fB-debug_pointer,\fR same as "dp"
.IP
nodebug_pointer disable \fB-debug_pointer,\fR same as "nodp"
.IP
debug_keyboard   enable  \fB-debug_keyboard,\fR same as "dk"
.IP
nodebug_keyboard disable \fB-debug_keyboard,\fR same as "nodk"
.IP
defer:n         set \fB-defer\fR to n ms,same as deferupdate:n
.IP
wait:n          set \fB-wait\fR to n ms.
.IP
rfbwait:n       set \fB-rfbwait\fR (rfbMaxClientWait) to n ms.
.IP
nap             enable  \fB-nap\fR mode.
.IP
nonap           disable \fB-nap\fR mode.
.IP
sb:n            set \fB-sb\fR to n s, same as screen_blank:n
.IP
fs:frac         set \fB-fs\fR fraction to "frac", e.g. 0.5
.IP
gaps:n          set \fB-gaps\fR to n.
.IP
grow:n          set \fB-grow\fR to n.
.IP
fuzz:n          set \fB-fuzz\fR to n.
.IP
snapfb          enable  \fB-snapfb\fR mode.
.IP
nosnapfb        disable \fB-snapfb\fR mode.
.IP
progressive:n   set libvncserver \fB-progressive\fR slice
                height parameter to n.
.IP
desktop:str     set \fB-desktop\fR name to str for new clients.
.IP
rfbport:n       set \fB-rfbport\fR to n.
.IP
http            enable  http client connections.
.IP
nohttp          disable http client connections.
.IP
httpport:n      set \fB-httpport\fR to n.
.IP
httpdir:dir     set \fB-httpdir\fR to dir (and enable http).
.IP
enablehttpproxy   enable  \fB-enablehttpproxy\fR mode.
.IP
noenablehttpproxy disable \fB-enablehttpproxy\fR mode.
.IP
alwaysshared     enable  \fB-alwaysshared\fR mode.
.IP
noalwaysshared   disable \fB-alwaysshared\fR mode.
                (may interfere with other options)
.IP
nevershared      enable  \fB-nevershared\fR mode.
.IP
nonevershared    disable \fB-nevershared\fR mode.
                (may interfere with other options)
.IP
dontdisconnect   enable  \fB-dontdisconnect\fR mode.
.IP
nodontdisconnect disable \fB-dontdisconnect\fR mode.
                (may interfere with other options)
.IP
noremote        disable the \fB-remote\fR command processing,
                it cannot be turned back on.
.IP
.IP
The 
.IR vncconnect (1)
command from standard VNC
.IP
distributions may also be used if string is prefixed
.IP
with "cmd=" E.g. 'vncconnect cmd=stop'.  Under some
.IP
circumstances 
.IR xprop (1)
can used if it supports \fB-set\fR
.IP
(see the FAQ).
.IP
.IP
If "\fB-connect\fR \fI/path/to/file\fR" has been supplied to the
.IP
running x11vnc server then that file can be used as a
.IP
communication channel (this is the only way to remote
.IP
control one of many x11vnc's polling the same X display)
.IP
Simply run: 'x11vnc \fB-connect\fR /path/to/file \fB-remote\fR ...'
.IP
or you can directly write to the file via something
.IP
like: "echo cmd=stop > /path/to/file", etc.
.PP
\fB-query\fR \fIvariable\fR
.IP
Like \fB-remote,\fR except just query the value of
\fIvariable\fR.  "\fB-Q\fR" is an alias for "\fB-query\fR".
Multiple queries can be done by separating variables
by commas, e.g. \fB-query\fR var1,var2. The results come
back in the form ans=var1:value1,ans=var2:value2,...
to the standard output.  If a variable is read-only,
it comes back with prefix "aro=" instead of "ans=".
.IP
Some \fB-remote\fR commands are pure actions that do not make
sense as variables, e.g. "stop" or "disconnect",
in these cases the value returned is "N/A".  To direct
a query straight to the VNC_CONNECT property or connect
file use "qry=..." instead of "cmd=..."
.IP
Here is the current list of "variables" that can
be supplied to the \fB-query\fR command. This includes the
"N/A" ones that return no useful info.  For variables
names that do not correspond to an x11vnc option or
remote command, we hope the name makes it obvious what
the returned value corresponds to (hint: the ext_*
variables correspond to the presence of X extensions):
.IP
ans= stop quit exit shutdown ping blacken zero
refresh reset close disconnect id sid waitmapped
nowaitmapped flashcmap noflashcmap truecolor notruecolor
overlay nooverlay overlay_cursor overlay_yescursor
nooverlay_nocursor nooverlay_cursor nooverlay_yescursor
overlay_nocursor visual scale viewonly noviewonly
shared noshared forever noforever once timeout deny
lock nodeny unlock connect allowonce allow localhost
nolocalhost accept gone shm noshm flipbyteorder
noflipbyteorder onetile noonetile solid_color solid
nosolid blackout xinerama noxinerama xrandr noxrandr
xrandr_mode padgeom quiet q noquiet modtweak nomodtweak
xkb noxkb skip_keycodes add_keysyms noadd_keysyms
clear_mods noclear_mods clear_keys noclear_keys
remap repeat norepeat fb nofb bell nobell sel
nosel primary noprimary cursorshape nocursorshape
cursorpos nocursorpos cursor show_cursor noshow_cursor
nocursor xfixes noxfixes alphacut alphafrac alpharemove
noalpharemove alphablend noalphablend xwarp xwarppointer
noxwarp noxwarppointer buttonmap dragging nodragging
pointer_mode pm input_skip input client_input speeds
debug_pointer dp nodebug_pointer nodp debug_keyboard dk
nodebug_keyboard nodk deferupdate defer wait rfbwait
nap nonap sb screen_blank fs gaps grow fuzz snapfb
nosnapfb progressive rfbport http nohttp httpport
httpdir enablehttpproxy noenablehttpproxy alwaysshared
noalwaysshared nevershared noalwaysshared dontdisconnect
nodontdisconnect desktop noremote
.IP
aro=  display vncdisplay desktopname http_url auth
users rootshift scale_str scaled_x scaled_y scale_numer
scale_denom scale_fac scaling_noblend scaling_nomult4
scaling_pad scaling_interpolate inetd safer unsafe
passwdfile using_shm logfile o rc norc h help V version
lastmod bg sigpipe threads clients client_count pid
ext_xtest ext_xkb ext_xshm ext_xinerama ext_overlay
ext_xfixes ext_xdamage ext_xrandr rootwin num_buttons
button_mask mouse_x mouse_y bpp depth indexed_color
dpy_x dpy_y rfbauth passwd
.PP
\fB-sync\fR
.IP
By default \fB-remote\fR commands are run asynchronously, that
is, the request is posted and the program immediately
exits.  Use \fB-sync\fR to have the program wait for an
acknowledgement from the x11vnc server that command
was processed.  On the other hand \fB-query\fR requests are
always processed synchronously because they have wait
for the result.
.IP
Also note that if both \fB-remote\fR and \fB-query\fR requests are
supplied on the command line, the \fB-remote\fR is processed
first (synchronously: no need for \fB-sync),\fR and then
the \fB-query\fR request is processed in the normal way.
This allows for a reliable way to see if the \fB-remote\fR
command was processed by querying for any new settings.
Note however that there is timeout of a few seconds so
if the x11vnc takes longer than that to process the
requests the requestor will think that a failure has
taken place.
.PP
\fB-noremote\fR
.IP
Do not process any remote control commands or queries.
.IP
A note about security wrt remote control commands.
If someone can connect to the X display and change the
property VNC_CONNECT, then they can remotely control
x11vnc.  Normally access to the X display is protected.
Note that if they can modify VNC_CONNECT, they could
also run their own x11vnc and have complete control
of the desktop.  If the  "\fB-connect\fR \fI/path/to/file\fR"
channel is being used, obviously anyone who can
write to /path/to/file can remotely control x11vnc.
So be sure to protect the X display and that file's
write permissions.
.IP
To disable the VNC_CONNECT property channel completely
use \fB-novncconnect.\fR
.PP
\fB-unsafe\fR
.IP
If x11vnc is running as root (e.g. inetd or Xsetup for
a display manager) a few remote commands are disabled
(currently: id:pick, accept:<cmd>, and gone:<cmd>)
because they are associated with running external
programs.  If you specify \fB-unsafe,\fR then these remote
control commands are allowed when running as root.
When running as non-root all commands are allowed.
See \fB-safer\fR below.
.PP
\fB-safer\fR
.IP
Even if not running as root, disable the above unsafe
remote control commands.
.PP
\fB-deny_all\fR
.IP
For use with \fB-remote\fR nodeny: start out denying all
incoming clients until "\fB-remote\fR \fInodeny\fR" is used to
let them in.
.PP
These options are passed to libvncserver:
.PP
\fB-rfbport\fR \fIport\fR
.IP
TCP port for RFB protocol
.PP
\fB-rfbwait\fR \fItime\fR
.IP
max time in ms to wait for RFB client
.PP
\fB-rfbauth\fR \fIpasswd-file\fR
.IP
use authentication on RFB protocol
(use 'storepasswd' to create a password file)
.PP
\fB-passwd\fR \fIplain-password\fR
.IP
use authentication
(use plain-password as password, USE AT YOUR RISK)
.PP
\fB-deferupdate\fR \fItime\fR
.IP
time in ms to defer updates (default 40)
.PP
\fB-desktop\fR \fIname\fR
.IP
VNC desktop name (default "LibVNCServer")
.PP
\fB-alwaysshared\fR
.IP
always treat new clients as shared
.PP
\fB-nevershared\fR
.IP
never treat new clients as shared
.PP
\fB-dontdisconnect\fR
.IP
don't disconnect existing clients when a new non-shared
connection comes in (refuse new connection instead)
.PP
\fB-httpdir\fR \fIdir-path\fR
.IP
enable http server using dir-path home
.PP
\fB-httpport\fR \fIportnum\fR
.IP
use portnum for http connection
.PP
\fB-enablehttpproxy\fR
.IP
enable http proxy support
.PP
\fB-progressive\fR \fIheight\fR
.IP
enable progressive updating for slow links
.SH "FILES"
.IR $HOME/.x11vncrc ,
.IR $HOME/.Xauthority
.SH "ENVIRONMENT"
.IR DISPLAY ,
.IR XAUTHORITY ,
.IR HOME
.PP
The following are set for the auxiliary commands
run by \fB-accept\fR and \fB-gone\fR:
.PP
.IR RFB_CLIENT_IP ,
.IR RFB_CLIENT_PORT ,
.IR RFB_SERVER_IP ,
.IR RFB_SERVER_PORT ,
.IR RFB_X11VNC_PID ,
.IR RFB_CLIENT_ID ,
.IR RFB_CLIENT_COUNT ,
.IR RFB_MODE
.SH "SEE ALSO"
.IR vncviewer (1),
.IR vncpasswd (1),
.IR vncconnect (1),
.IR vncserver (1),
.IR Xvnc (1),
.IR inetd (1),
.IR xev (1),
.IR xmodmap (1),
.IR Xserver (1),
.IR xauth (1),
.IR xhost (1),
.IR Xsecurity (7),
.IR xmessage (1),
.IR ipcrm (1),
.IR http://www.tightvnc.com ,
.IR http://www.realvnc.com ,
.IR http://www.karlrunge.com/x11vnc/ ,
.IR http://www.karlrunge.com/x11vnc/#faq
.SH AUTHORS
x11vnc was written by Karl J. Runge <runge@karlrunge.com>,
it is part of the LibVNCServer project <http://sf.net/projects/libvncserver>.
This manual page is based one the one written by Ludovic Drolez
<ldrolez@debian.org>, for the Debian project (both may be used by others).