NAME
Xserver - X Window System display server

SYNOPSIS
X [option ...]

DESCRIPTION
X is the generic name for the X Window System display
server. On MachTen and XTen systems it is a link to the
binary image XMachTen.

STARTING THE SERVER
The X server is started via different methods on MachTen and
XTen. See XMachTen(n) for more details on X server startup
and shutdown.

OPTIONS
The MachTen X servers accept the following command line
options:

:displaynumber
the X server runs as the given displaynumber, which
by default is 0. If multiple X servers are to run
simultaneously on a host, each must have a unique
display number. See the DISPLAY NAMES section of
the X(3) manual page to learn how to specify which
display number clients should try to use.

-ac disables host-based access control mechanisms.
Enables access by any host, and permits any host to
modify the access control list. Use with extreme
caution. This option exists primarily for running
test suites remotely.

-audit level
Sets the audit trail level. The default level is 1,
meaning only connection rejections are reported.
Level 2 additionally reports all successful connec-
tions and disconnects. Level 0 turns off the audit
trail. Audit lines are sent as standard error out-
put.

-auth authorization-file
Specifies a file which contains a collection of
authorization records used to authenticate access.
See also the xdm and Xsecurity manual pages.

bc disables certain kinds of error checking, for bug
compatibility with previous releases (e.g., to work
around bugs in R2 and R3 xterms and toolkits).
Deprecated.

-bs disables backing store support on all screens.

-cmdkey alt
specifies that the Macintosh Command (Apple) key
will be used as an X Alt key. The default operation
of the Macintosh Command key is the X Meta charac-
ter.

-co filename
sets name of RGB color database. The default is
<XRoot>/lib/X11/rgb, where <XRoot> refers to the
root of the X11 install tree.

-config filename
reads more options from the given file. Options in
the file may be separated by newlines if desired.
If a ’#’ character appears on a line, all characters
between it and the next newline are ignored, provid-
ing a simple commenting facility. The -config
option itself may appear in the file.

-dpi resolution
sets the resolution of the screen, in dots per inch.
To be used when the server cannot determine the
screen size from the hardware.

-deferglyphs whichfonts
specifies the types of fonts for which the server
should attempt to use deferred glyph loading. whi-
chfonts can be all (all fonts),

-fc cursorFont
sets default cursor font.

-fn font
sets the default font.

-fp fontPath
sets the search path for fonts. This path is a
comma separated list of directories which the X
server searches for font databases.

-fs starts the server in full screen mode. In this
mode, the Macintosh menu bar is hidden by the X
desktop. Pull down menus from the Mac menu bar
remain accessible by pressing the mouse button while
dragging the cursor along the top edge of the X
desktop.

-help prints a usage message.

-I causes all remaining command line arguments to be
ignored.

-mbm middle-key
changes the middle mouse button keystroke mapping
from the default <left arrow> key. The key is
entered as a decimal value representing the Macin-
tosh virtual key code corresponding to the desired
key. Allowable values are between 0 and 127.

-mbr right-key
changes the right mouse button keystroke mapping
from the default <right arrow> key.

-menu starts the server in dedicated full screen mode. In
this mode, the Macintosh menu bar is hidden and
access to Mac pull down menus is completely dis-
abled. Access to the Macintosh desktop is allowed
only via the xtmenu(9) program. Use this option
with extreme caution, as it effectively locks out
the Macintosh desktop GUI enviroment when the X
desktop is visible!

-mo specifies that the Macintosh Option key will be used
in combination with the mouse button keystroke to
simulate the middle or right mouse button. When
used without the -mbm or -mbr start up options, the
default middle and right mouse button keystrokes
become <Option-left arrow> and <Option-right arrow>,
respectively. This option also causes the <up
arrow> and <down arrow> keys to function normally.

-pn permits the server to continue running if it fails
to establish all of its well-known sockets (connec-
tion points for clients), but establishes at least
one.

-swc runs the server with a software cursor, allowing
oversized X client specified cursors with a slight
tradeoff in tactile response. Specifying this
option will force the server to operate in full
screen mode (refer to the "-menu" option).

-su disables save under support on all screens.

-terminate
causes the server to terminate at server reset,
instead of continuing to run.

-to seconds
sets default connection timeout in seconds.

-tst disables all testing extensions (e.g., XTEST, XTrap,
XTestExtension1).

ttyxx ignored, for servers started the ancient way (from
init).

-wm forces the default backing-store of all windows to
be WhenMapped. This is a backdoor way of getting
backing-store to apply to all windows. Although all
mapped windows will have backing store, the backing
store attribute value reported by the server for a
window will be the last value established by a
client. If it has never been set by a client, the
server will report the default value, NotUseful.
This behavior is required by the X protocol, which
allows the server to exceed the client’s backing
store expectations but does not provide a way to
tell the client that it is doing so.

-x extension
loads the specified extension at init. This is a
no-op for most implementations.

SERVER DEPENDENT OPTIONS
Some X servers accept the following options:

-ld kilobytes
sets the data space limit of the server to the
specified number of kilobytes. A value of zero
makes the data size as large as possible. The
default value of -1 leaves the data space limit
unchanged.

-lf files
sets the number-of-open-files limit of the server to
the specified number. A value is zero makes the
limit as large as possible. The default value of -1
leaves the limit unchanged.

-ls kilobytes
sets the stack space limit of the server to the
specified number of kilobytes. A value of zero
makes the stack size as large as possible. The
default value of -1 leaves the stack space limit
unchanged.

XDMCP OPTIONS
X servers that support XDMCP have the following options.
See the X Display Manager Control Protocol specification for
more information.

-query host-name
Enable XDMCP and send Query packets to the specified
host.

-broadcast
Enable XDMCP and broadcast BroadcastQuery packets to
the network. The first responding display manager
will be chosen for the session.

-indirect host-name
Enable XDMCP and send IndirectQuery packets to the
specified host.

-port port-num
Use an alternate port number for XDMCP packets.
Must be specified before any -query, -broadcast or
-indirect options.

-class display-class
XDMCP has an additional display qualifier used in
resource lookup for display-specific options. This
option sets that value, by default it is "MIT-
Unspecified" (not a very useful value).

-cookie xdm-auth-bits
When testing XDM-AUTHENTICATION-1, a private key is
shared between the server and the manager. This
option sets the value of that private data (not that
it is very private, being on the command line!).

-displayID display-id
Yet another XDMCP specific value, this one allows
the display manager to identify each display so that
it can locate the shared key.

XKEYBOARD OPTIONS
X servers that support the XKEYBOARD extension accept the
following options:

-xkbdir directory
base directory for keyboard layout files

-xkbmap filename
keyboard description to load on startup

[+-]accessx
enable(+) or disable(-) AccessX key sequences

Many servers also have device-specific command line options.
See the manual pages for the individual servers for more
details.

NETWORK CONNECTIONS
The X server supports client connections via a platform-
dependent subset of the following transport types: TCP/IP,
Unix Domain sockets, DECnet, and several varieties of SVR4
local connections. See the DISPLAY NAMES section of the
X(3) manual page to learn how to specify which transport
type clients should try to use.

SECURITY
The X server implements a platform-dependent subset of the
following authorization protocols: MIT-MAGIC-COOKIE-1, XDM-
AUTHORIZATION-1, SUN-DES-1, and MIT-KERBEROS-5. See the
Xsecurity(3) manual page for information on the operation of
these protocols.

Authorization data required by the above protocols is passed
to the server in a private file named with the -auth command
line option. Each time the server is about to accept the
first connection after a reset (or when the server is start-
ing), it reads this file. If this file contains any author-
ization records, the local host is not automatically allowed
access to the server, and only clients which send one of the
authorization records contained in the file in the connec-
tion setup information will be allowed access. See the Xau
manual page for a description of the binary format of this
file. See xauth(1) for maintenance of this file, and dis-
tribution of its contents to remote hosts.

The X server also uses a host-based access control list for
deciding whether or not to accept connections from clients
on a particular machine. If no other authorization mechan-
ism is being used, this list initially consists of the host
on which the server is running as well as any machines
listed in the file /etc/Xn.hosts, where n is the display
number of the server. Each line of the file should contain
either an Internet hostname (e.g. expo.lcs.mit.edu) or a
DECnet hostname in double colon format (e.g. hydra::).
There should be no leading or trailing spaces on any lines.
For example:

joesworkstation
corporate.company.com
star::
bigcpu::

Users can add or remove hosts from this list and enable or
disable access control using the xhost command from the same
machine as the server.

The X protocol intrinsically does not have any notion of
window operation permissions or place any restrictions on
what a client can do; if a program can connect to a display,
it has full run of the screen. Sites that have better
authentication and authorization systems might wish to make
use of the hooks in the libraries and the server to provide
additional security models.

SIGNALS
The X server attaches special meaning to the following sig-
nals:

SIGHUP SIGTERM This signal causes the server to close all
existing connections, free all resources, and
restore all defaults. It is sent by the display
manager whenever the main user’s main application
(usually an xterm or window manager) exits to force
the server to exit cleanly.

SIGUSR1 This signal is used quite differently from either of
the above. When the server starts, it checks to see
if it has inherited SIGUSR1 as SIG_IGN instead of
the usual SIG_DFL. In this case, the server sends a
SIGUSR1 to its parent process after it has set up
the various connection schemes. Xdm uses this
feature to recognize when connecting to the server
is possible.

FONTS
The X server can obtain fonts from directories and/or from
font servers. The list of directories and font servers the
X server uses when trying to open a font is controlled by
the font path.

The default font path is "<XRoot>/lib/X11/fonts/misc/,
<XRoot>/lib/X11/fonts/Speedo/, <XRoot>/lib/X11/fonts/Type1/,
<XRoot>/lib/X11/fonts/75dpi/, <XRoot>/lib/X11/fonts/100dpi/
where <XRoot> refers to the root of the X11 install tree.

The font path can be set with the -fp option or by xset(1)
after the server has started.

Font databases are created by running the mkfontdir program
in the directory containing the compiled versions of the
fonts (the .pcf files). Whenever fonts are added to a
directory, mkfontdir should be rerun so that the server can
find the new fonts. If mkfontdir is not run, the server
will not be able to find any fonts in the directory.

FILES
/etc/Xn.hosts Initial access control list
for display number n

<XRoot>/lib/X11/fonts/100dpi
<XRoot>/lib/X11/fonts/misc, <XRoot>/lib/X11/fonts/75dpi,
Bitmap font directories

<XRoot>/lib/X11/fonts/Speedo, <XRoot>/lib/X11/fonts/Type1
Outline font directories

<XRoot>/lib/X11/fonts/PEX PEX font directories

<XRoot>/lib/X11/rgb.txt Color database

/tmp/.X11-unix/Xn Unix domain socket for display
number n

/tmp/rcXn Kerberos 5 replay cache for
display number n

/usr/adm/Xnmsgs Error log file for display
number n if run from init(8)

<XRoot>/lib/X11/xdm/xdm-errors
Default error log file if the
server is run from xdm(1)

Note: <XRoot> refers to the root of the X11 install tree.