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NAME
X - a portable, network-transparent window system
SYNOPSIS
The X Window System is a network transparent window system developed
at MIT which runs on a wide range of computing and graphics machines.
It should be relatively straightforward to build the MIT software
distribution on most ANSI C and POSIX compliant systems. Commercial
implementations are also available for a wide range of platforms.
The X Consortium requests that the following names be used when
referring to this software:
X
X Window System
X Version 11
X Window System, Version 11
X11
X Window System is a trademark of the Massachusetts Institute of
Technology.
DESCRIPTION
X Window System servers run on computers with bitmap displays. The
server distributes user input to and accepts output requests from
various client programs through a variety of different interprocess
communication channels. Although the most common case is for the
client programs to be running on the same machine as the server,
clients can be run transparently from other machines (including
machines with different architectures and operating systems) as well.
X supports overlapping hierarchical subwindows and text and graphics
operations, on both monochrome and color displays. For a full
explanation of the functions that are available, see the Xlib - C
Language X Interface manual, the X Window System Protocol
specification, the X Toolkit Intrinsics - C Language Interface
manual, and various toolkit documents.
The number of programs that use X is quite large. Programs provided
in the core MIT distribution include: a terminal emulator (xterm), a
window manager (twm), a display manager (xdm), a console redirect
program (xconsole), mail managing utilities (xmh and xbiff), a manual
page browser (xman), a bitmap editor (bitmap), a resource editor
(editres), a ditroff previewer (xditview), access control programs
(xauth and xhost), user preference setting programs (xrdb, xcmsdb,
xset, xsetroot, xstdcmap, and xmodmap), a load monitor (xload),
clocks (xclock and oclock), a font displayer (xfd), utilities for
listing information about fonts, windows, and displays (xlsfonts,
xfontsel, xwininfo, xlsclients, xdpyinfo, and xprop), a diagnostic
for seeing what events are generated and when (xev), screen image
manipulation utilities (xwd, xwud, xpr, and xmag), and various demos
(xeyes, ico, xgc, x11perf, etc.).
Many other utilities, window managers, games, toolkits, etc. are
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included as user-contributed software in the MIT distribution, or are
available using anonymous ftp on the Internet. See your site
administrator for details.
STARTING UP
There are two main ways of getting the X server and an initial set of
client applications started. The particular method used depends on
what operating system you are running and on whether or not you use
other window systems in addition to X.
xdm (the X Display Manager)
If you want to always have X running on your display, your
site administrator can set your machine up to use the X
Display Manager xdm. This program is typically started by
the system at boot time and takes care of keeping the server
running and getting users logged in. If you are running xdm,
you will see a window on the screen welcoming you to the
system and asking for your username and password. Simply
type them in as you would at a normal terminal, pressing the
Return key after each. If you make a mistake, xdm will
display an error message and ask you to try again. After you
have successfully logged in, xdm will start up your X
environment. By default, if you have an executable file
named .xsession in your home directory, xdm will treat it as
a program (or shell script) to run to start up your initial
clients (such as terminal emulators, clocks, a window
manager, user settings for things like the background, the
speed of the pointer, etc.). Your site administrator can
provide details.
xinit (run manually from the shell)
Sites that support more than one window system might choose
to use the xinit program for starting X manually. If this is
true for your machine, your site administrator will probably
have provided a program named "x11", "startx", or "xstart"
that will do site-specific initialization (such as loading
convenient default resources, running a window manager,
displaying a clock, and starting several terminal emulators)
in a nice way. If not, you can build such a script using the
xinit program. This utility simply runs one user-specified
program to start the server, runs another to start up any
desired clients, and then waits for either to finish. Since
either or both of the user-specified programs may be a shell
script, this gives substantial flexibility at the expense of
a nice interface. For this reason, xinit is not intended for
end users.
DISPLAY NAMES
From the user's prospective, every X server has a display name of the
form:
hostname:displaynumber.screennumber
This information is used by the application to determine how it
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should connect to the server and which screen it should use by
default (on displays with multiple monitors):
hostname
The hostname specifies the name of the machine to which the
display is physically connected. If the hostname is not
given, the most efficient way of communicating to a server on
the same machine will be used.
displaynumber
The phrase "display" is usually used to refer to collection
of monitors that share a common keyboard and pointer (mouse,
tablet, etc.). Most workstations tend to only have one
keyboard, and therefore, only one display. Larger, multi-
user systems, however, will frequently have several displays
so that more than one person can be doing graphics work at
once. To avoid confusion, each display on a machine is
assigned a display number (beginning at 0) when the X server
for that display is started. The display number must always
be given in a display name.
screennumber
Some displays share a single keyboard and pointer among two
or more monitors. Since each monitor has its own set of
windows, each screen is assigned a screen number (beginning
at 0) when the X server for that display is started. If the
screen number is not given, then screen 0 will be used.
On POSIX systems, the default display name is stored in your DISPLAY
environment variable. This variable is set automatically by the
xterm terminal emulator. However, when you log into another machine
on a network, you'll need to set DISPLAY by hand to point to your
display. For example,
% setenv DISPLAY myws:0
$ DISPLAY=myws:0; export DISPLAY
The xon script can be used to start an X program on a remote machine;
it automatically sets the DISPLAY variable correctly.
Finally, most X programs accept a command line option of -display
displayname to temporarily override the contents of DISPLAY. This is
most commonly used to pop windows on another person's screen or as
part of a "remote shell" command to start an xterm pointing back to
your display. For example,
% xeyes -display joesws:0 -geometry 1000x1000+0+0
% rsh big xterm -display myws:0 -ls </dev/null &
X servers listen for connections on a variety of different
communications channels (network byte streams, shared memory, etc.).
Since there can be more than one way of contacting a given server,
The hostname part of the display name is used to determine the type
of channel (also called a transport layer) to be used. X servers
generally support the following types of connections:
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local
The hostname part of the display name should be the empty
string. For example: :0, :1, and :0.1. The most efficient
local transport will be chosen.
TCPIP
The hostname part of the display name should be the server
machine's IP address name. Full Internet names, abbreviated
names, and IP addresses are all allowed. For example:
expo.lcs.mit.edu:0, expo:0, 18.30.0.212:0, bigmachine:1, and
hydra:0.1.
DECnet
The hostname part of the display name should be the server
machine's nodename followed by two colons instead of one.
For example: myws::0, big::1, and hydra::0.1.
ACCESS CONTROL
An X server can use several types of access control. Mechanisms
provided in Release 5 are:
Host Access Simple host-based access control.
MIT-MAGIC-COOKIE-1 Shared plain-text "cookies".
XDM-AUTHORIZATION-1 Secure DES based private-keys.
SUN-DES-1 Based on Sun's secure rpc system.
Xdm initializes access control for the server, and also places
authorization information in a file accessible to the user.
Normally, the list of hosts from which connections are always
accepted should be empty, so that only clients with are explicitly
authorized can connect to the display. When you add entries to the
host list (with xhost), the server no longer performs any
authorization on connections from those machines. Be careful with
this.
The file from which Xlib extracts authorization data can be specified
with the environment variable XAUTHORITY, and defaults to the file
.Xauthority in the home directory. Xdm uses $HOME/.Xauthority and
will create it or merge in authorization records if it already exists
when a user logs in.
If you use several machines, and share a common home directory across
all of the machines by means of a network file system, then you never
really have to worry about authorization files, the system should
work correctly by default. Otherwise, as the authorization files are
machine-independent, you can simply copy the files to share them. To
manage authorization files, use xauth. This program allows you to
extract records and insert them into other files. Using this, you
can send authorization to remote machines when you login, if the
remote machine does not share a common home directory with your local
machine. Note that authorization information transmitted ``in the
clear'' through a network file system or using ftp or rcp can be
``stolen'' by a network eavesdropper, and as such may enable
unauthorized access. In many environments this level of security is
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not a concern, but if it is, you need to know the exact semantics of
the particular authorization data to know if this is actually a
problem.
For more information on access control, see the Xsecurity manual
page.
GEOMETRY SPECIFICATIONS
One of the advantages of using window systems instead of hardwired
terminals is that applications don't have to be restricted to a
particular size or location on the screen. Although the layout of
windows on a display is controlled by the window manager that the
user is running (described below), most X programs accept a command
line argument of the form -geometry WIDTHxHEIGHT+XOFF+YOFF (where
WIDTH, HEIGHT, XOFF, and YOFF are numbers) for specifying a preferred
size and location for this application's main window.
The WIDTH and HEIGHT parts of the geometry specification are usually
measured in either pixels or characters, depending on the
application. The XOFF and YOFF parts are measured in pixels and are
used to specify the distance of the window from the left or right and
top and bottom edges of the screen, respectively. Both types of
offsets are measured from the indicated edge of the screen to the
corresponding edge of the window. The X offset may be specified in
the following ways:
+XOFF The left edge of the window is to be placed XOFF pixels in
from the left edge of the screen (i.e. the X coordinate of
the window's origin will be XOFF). XOFF may be negative, in
which case the window's left edge will be off the screen.
-XOFF The right edge of the window is to be placed XOFF pixels in
from the right edge of the screen. XOFF may be negative, in
which case the window's right edge will be off the screen.
The Y offset has similar meanings:
+YOFF The top edge of the window is to be YOFF pixels below the top
edge of the screen (i.e. the Y coordinate of the window's
origin will be YOFF). YOFF may be negative, in which case
the window's top edge will be off the screen.
-YOFF The bottom edge of the window is to be YOFF pixels above the
bottom edge of the screen. YOFF may be negative, in which
case the window's bottom edge will be off the screen.
Offsets must be given as pairs; in other words, in order to specify
either XOFF or YOFF both must be present. Windows can be placed in
the four corners of the screen using the following specifications:
+0+0 upper left hand corner.
-0+0 upper right hand corner.
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-0-0 lower right hand corner.
+0-0 lower left hand corner.
In the following examples, a terminal emulator will be placed in
roughly the center of the screen and a load average monitor, mailbox,
and clock will be placed in the upper right hand corner:
xterm -fn 6x10 -geometry 80x24+30+200 &
xclock -geometry 48x48-0+0 &
xload -geometry 48x48-96+0 &
xbiff -geometry 48x48-48+0 &
WINDOW MANAGERS
The layout of windows on the screen is controlled by special programs
called window managers. Although many window managers will honor
geometry specifications as given, others may choose to ignore them
(requiring the user to explicitly draw the window's region on the
screen with the pointer, for example).
Since window managers are regular (albeit complex) client programs, a
variety of different user interfaces can be built. The MIT
distribution comes with a window manager named twm which supports
overlapping windows, popup menus, point-and-click or click-to-type
input models, title bars, nice icons (and an icon manager for those
who don't like separate icon windows).
See the user-contributed software in the MIT distribution for other
popular window managers.
FONT NAMES
Collections of characters for displaying text and symbols in X are
known as fonts. A font typically contains images that share a common
appearance and look nice together (for example, a single size,
boldness, slant, and character set). Similarly, collections of fonts
that are based on a common type face (the variations are usually
called roman, bold, italic, bold italic, oblique, and bold oblique)
are called families.
Fonts come in various sizes. The X server supports scalable fonts,
meaning it is possible to create a font of arbitrary size from a
single source for the font. The server supports scaling from outline
fonts and bitmap fonts. Scaling from outline fonts usually produces
significantly better results than scaling from bitmap fonts.
An X server can obtain fonts from individual files stored in
directories in the file system, or from one or more font servers, or
from a mixtures of directories and font servers. The list of places
the server looks when trying to find a font is controlled by its font
path. Although most installations will choose to have the server
start up with all of the commonly used font directories in the font
path, the font path can be changed at any time with the xset program.
However, it is important to remember that the directory names are on
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the server's machine, not on the application's. The most common
fonts use by X servers and font servers can be found in four
directories:
/usr/lib/X11/fonts/misc
This directory contains many miscellaneous bitmap fonts that
are useful on all systems. It contains a family of fixed-
width fonts, a family of fixed-width fonts from Dale
Schumacher, several Kana fonts from Sony Corporation, two JIS
Kanji fonts, two Hangul fonts from Daewoo Electronics, two
Hebrew fonts from Joseph Friedman, the standard cursor font,
two cursor fonts from Digital Equipment Corporation, and
cursor and glyph fonts from Sun Microsystems. It also has
various font name aliases for the fonts, including fixed and
variable.
/usr/lib/X11/fonts/Speedo
This directory contains outline fonts for Bitstream's Speedo
rasterizer. A single font face, in normal, bold, italic, and
bold italic, is provided, contributed by Bitstream, Inc.
/usr/lib/X11/fonts/75dpi
This directory contains bitmap fonts contributed by Adobe
Systems, Inc., Digital Equipment Corporation, Bitstream,
Inc., Bigelow and Holmes, and Sun Microsystems, Inc. for 75
dots per inch displays. An integrated selection of sizes,
styles, and weights are provided for each family.
/usr/lib/X11/fonts/100dpi
This directory contains 100 dots per inch versions of some of
the fonts in the 75dpi directory.
Bitmap font files are usually created by compiling a textual font
description into binary form, using bdftopcf. Font databases are
created by running the mkfontdir program in the directory containing
the source or compiled versions of the fonts. Whenever fonts are
added to a directory, mkfontdir should be rerun so that the server
can find the new fonts. To make the server reread the font database,
reset the font path with the xset program. For example, to add a
font to a private directory, the following commands could be used:
% cp newfont.pcf ~/myfonts
% mkfontdir ~/myfonts
% xset fp rehash
The xfontsel and xlsfonts programs can be used to browse through the
fonts available on a server. Font names tend to be fairly long as
they contain all of the information needed to uniquely identify
individual fonts. However, the X server supports wildcarding of font
names, so the full specification
-adobe-courier-medium-r-normal--10-100-75-75-m-60-iso8859-1
might be abbreviated as:
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-*-courier-medium-r-normal--*-100-*-*-*-*-iso8859-1
Because the shell also has special meanings for * and ?, wildcarded
font names should be quoted:
% xlsfonts -fn '-*-courier-medium-r-normal--*-100-*-*-*-*-*-*'
The xlsfonts program can be used to list all of the fonts that match
a given pattern. With no arguments, it lists all available fonts.
This will usually list the same font at many different sizes. To see
just the base scalable font names, try using one of the following
patterns:
-*-*-*-*-*-*-0-0-0-0-*-0-*-*
-*-*-*-*-*-*-0-0-75-75-*-0-*-*
-*-*-*-*-*-*-0-0-100-100-*-0-*-*
To convert one of the resulting names into a font at a specific size,
replace one of the first two zeros with a nonzero value. The field
containing the first zero is for the pixel size; replace it with a
specific height in pixels to name a font at that size.
Alternatively, the field containing the second zero is for the point
size; replace it with a specific size in decipoints (there are 722.7
decipoints to the inch) to name a font at that size. The last zero
is an average width field, measured in tenths of pixels; some servers
will anamorphically scale if this value is specified.
FONT SERVER NAMES
One of the following forms can be used to name a font server that
accepts TCP connections:
tcp/hostname:port
tcp/hostname:port/cataloguelist
The hostname specifies the name (or decimal numeric address) of the
machine on which the font server is running. The port is the decimal
TCP port on which the font server is listening for connections. The
cataloguelist specifies a list of catalogue names, with '+' as a
separator.
Examples: tcp/expo.lcs.mit.edu:7000, tcp/18.30.0.212:7001/all.
One of the following forms can be used to name a font server that
accepts DECnet connections:
decnet/nodename::font$objname
decnet/nodename::font$objname/cataloguelist
The nodename specifies the name (or decimal numeric address) of the
machine on which the font server is running. The objname is a
normal, case-insensitive DECnet object name. The cataloguelist
specifies a list of catalogue names, with '+' as a separator.
Examples: DECnet/SRVNOD::FONT$DEFAULT,
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decnet/44.70::font$special/symbols.
COLOR NAMES
Most applications provide ways of tailoring (usually through
resources or command line arguments) the colors of various elements
in the text and graphics they display. A color can be specified
either by an abstract color name, or by a numerical color
specification. The numerical specification can identify a color in
either device-dependent (RGB) or device-independent terms. Color
strings are case-insensitive.
X supports the use of abstract color names, for example, "red",
"blue". A value for this abstract name is obtained by searching one
or more color name databases. Xlib first searches zero or more
client-side databases; the number, location, and content of these
databases is implementation dependent. If the name is not found, the
color is looked up in the X server's database. The text form of this
database is commonly stored in the file /usr/lib/X11/rgb.txt.
A numerical color specification consists of a color space name and a
set of values in the following syntax:
<colorspacename>:<value>/.../<value>
An RGB Device specification is identified by the prefix "rgb:" and
has the following syntax:
rgb:<red>/<green>/<blue>
<red>, <green>, <blue> := h | hh | hhh | hhhh
h := single hexadecimal digits
Note that h indicates the value scaled in 4 bits, hh the value scaled
in 8 bits, hhh the value scaled in 12 bits, and hhhh the value scaled
in 16 bits, respectively. These values are passed directly to the X
server, and are assumed to be gamma corrected.
The eight primary colors can be represented as:
black rgb:0/0/0
red rgb:ffff/0/0
green rgb:0/ffff/0
blue rgb:0/0/ffff
yellow rgb:ffff/ffff/0
magenta rgb:ffff/0/ffff
cyan rgb:0/ffff/ffff
white rgb:ffff/ffff/ffff
For backward compatibility, an older syntax for RGB Device is
supported, but its continued use is not encouraged. The syntax is an
initial sharp sign character followed by a numeric specification, in
one of the following formats:
#RGB (4 bits each)
#RRGGBB (8 bits each)
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#RRRGGGBBB (12 bits each)
#RRRRGGGGBBBB (16 bits each)
The R, G, and B represent single hexadecimal digits. When fewer than
16 bits each are specified, they represent the most-significant bits
of the value (unlike the "rgb:" syntax, in which values are scaled).
For example, #3a7 is the same as #3000a0007000.
An RGB intensity specification is identified by the prefix "rgbi:"
and has the following syntax:
rgbi:<red>/<green>/<blue>
The red, green, and blue are floating point values between 0.0 and
1.0, inclusive. They represent linear intensity values, with 1.0
indicating full intensity, 0.5 half intensity, and so on. These
values will be gamma corrected by Xlib before being sent to the X
server. The input format for these values is an optional sign, a
string of numbers possibly containing a decimal point, and an
optional exponent field containing an E or e followed by a possibly
signed integer string.
The standard device-independent string specifications have the
following syntax:
CIEXYZ:<X>/<Y>/<Z> (none, 1, none)
CIEuvY:<u>/<v>/<Y> (~.6, ~.6, 1)
CIExyY:<x>/<y>/<Y> (~.75, ~.85, 1)
CIELab:<L>/<a>/<b> (100, none, none)
CIELuv:<L>/<u>/<v> (100, none, none)
TekHVC:<H>/<V>/<C> (360, 100, 100)
All of the values (C, H, V, X, Y, Z, a, b, u, v, y, x) are floating
point values. Some of the values are constrained to be between zero
and some upper bound; the upper bounds are given in parentheses
above. The syntax for these values is an optional '+' or '-' sign, a
string of digits possibly containing a decimal point, and an optional
exponent field consisting of an 'E' or 'e' followed by an optional
'+' or '-' followed by a string of digits.
For more information on device independent color, see the Xlib
reference manual.
KEYBOARDS
The X keyboard model is broken into two layers: server-specific
codes (called keycodes) which represent the physical keys, and
server-independent symbols (called keysyms) which represent the
letters or words that appear on the keys. Two tables are kept in the
server for converting keycodes to keysyms:
modifier list
Some keys (such as Shift, Control, and Caps Lock) are known
as modifier and are used to select different symbols that are
attached to a single key (such as Shift-a generates a capital
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A, and Control-l generates a control character ^L). The
server keeps a list of keycodes corresponding to the various
modifier keys. Whenever a key is pressed or released, the
server generates an event that contains the keycode of the
indicated key as well as a mask that specifies which of the
modifier keys are currently pressed. Most servers set up
this list to initially contain the various shift, control,
and shift lock keys on the keyboard.
keymap table
Applications translate event keycodes and modifier masks into
keysyms using a keysym table which contains one row for each
keycode and one column for various modifier states. This
table is initialized by the server to correspond to normal
typewriter conventions. The exact semantics of how the table
is interpreted to produce keysyms depends on the particular
program, libraries, and language input method used, but the
following conventions for the first four keysyms in each row
are generally adhered to:
The first four elements of the list are split into two groups of
keysyms. Group 1 contains the first and second keysyms; Group 2
contains the third and fourth keysyms. Within each group, if the
first element is alphabetic and the the second element is the special
keysym NoSymbol, then the group is treated as equivalent to a group
in which the first element is the lowercase letter and the second
element is the uppercase letter.
Switching between groups is controlled by the keysym named MODE
SWITCH, by attaching that keysym to some key and attaching that key
to any one of the modifiers Mod1 through Mod5. This modifier is
called the ``group modifier.'' Group 1 is used when the group
modifier is off, and Group 2 is used when the group modifier is on.
Within a group, the modifier state determines which keysym to use.
The first keysym is used when the Shift and Lock modifiers are off.
The second keysym is used when the Shift modifier is on, when the
Lock modifier is on and the second keysym is uppercase alphabetic, or
when the Lock modifier is on and is interpreted as ShiftLock.
Otherwise, when the Lock modifier is on and is interpreted as
CapsLock, the state of the Shift modifier is applied first to select
a keysym; but if that keysym is lowercase alphabetic, then the
corresponding uppercase keysym is used instead.
OPTIONS
Most X programs attempt to use the same names for command line
options and arguments. All applications written with the X Toolkit
Intrinsics automatically accept the following options:
-display display
This option specifies the name of the X server to use.
-geometry geometry
This option specifies the initial size and location of the
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window.
-bg color, -background color
Either option specifies the color to use for the window
background.
-bd color, -bordercolor color
Either option specifies the color to use for the window
border.
-bw number, -borderwidth number
Either option specifies the width in pixels of the window
border.
-fg color, -foreground color
Either option specifies the color to use for text or
graphics.
-fn font, -font font
Either option specifies the font to use for displaying text.
-iconic
This option indicates that the user would prefer that the
application's windows initially not be visible as if the
windows had be immediately iconified by the user. Window
managers may choose not to honor the application's request.
-name
This option specifies the name under which resources for the
application should be found. This option is useful in shell
aliases to distinguish between invocations of an application,
without resorting to creating links to alter the executable
file name.
-rv, -reverse
Either option indicates that the program should simulate
reverse video if possible, often by swapping the foreground
and background colors. Not all programs honor this or
implement it correctly. It is usually only used on
monochrome displays.
+rv
This option indicates that the program should not simulate
reverse video. This is used to override any defaults since
reverse video doesn't always work properly.
-selectionTimeout
This option specifies the timeout in milliseconds within
which two communicating applications must respond to one
another for a selection request.
-synchronous
This option indicates that requests to the X server should be
sent synchronously, instead of asynchronously. Since Xlib
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normally buffers requests to the server, errors do not
necessarily get reported immediately after they occur. This
option turns off the buffering so that the application can be
debugged. It should never be used with a working program.
-title string
This option specifies the title to be used for this window.
This information is sometimes used by a window manager to
provide some sort of header identifying the window.
-xnllanguage language[territory][.codeset]
This option specifies the language, territory, and codeset
for use in resolving resource and other filenames.
-xrm resourcestring
This option specifies a resource name and value to override
any defaults. It is also very useful for setting resources
that don't have explicit command line arguments.
RESOURCES
To make the tailoring of applications to personal preferences easier,
X provides a mechanism for storing default values for program
resources (e.g. background color, window title, etc.) Resources are
specified as strings that are read in from various places when an
application is run. Program components are named in a hierarchical
fashion, with each node in the hierarchy identified by a class and an
instance name. At the top level is the class and instance name of
the application itself. By convention, the class name of the
application is the same as the program name, but with the first
letter capitalized (e.g. Bitmap or Emacs) although some programs that
begin with the letter ``x'' also capitalize the second letter for
historical reasons.
The precise syntax for resources is:
ResourceLine = Comment | IncludeFile | ResourceSpec | <empty line>
Comment = "!" {<any character except null or newline>}
IncludeFile = "#" WhiteSpace "include" WhiteSpace FileName WhiteSpace
FileName = <valid filename for operating system>
ResourceSpec = WhiteSpace ResourceName WhiteSpace ":" WhiteSpace Value
ResourceName = [Binding] {Component Binding} ComponentName
Binding = "." | "*"
WhiteSpace = {<space> | <horizontal tab>}
Component = "?" | ComponentName
ComponentName = NameChar {NameChar}
NameChar = "a"-"z" | "A"-"Z" | "0"-"9" | "_" | "-"
Value = {<any character except null or unescaped newline>}
Elements separated by vertical bar (|) are alternatives. Curly
braces ({...}) indicate zero or more repetitions of the enclosed
elements. Square brackets ([...]) indicate that the enclosed element
is optional. Quotes ("...") are used around literal characters.
IncludeFile lines are interpreted by replacing the line with the
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contents of the specified file. The word "include" must be in
lowercase. The filename is interpreted relative to the directory of
the file in which the line occurs (for example, if the filename
contains no directory or contains a relative directory
specification).
If a ResourceName contains a contiguous sequence of two or more
Binding characters, the sequence will be replaced with single "."
character if the sequence contains only "." characters, otherwise the
sequence will be replaced with a single "*" character.
A resource database never contains more than one entry for a given
ResourceName. If a resource file contains multiple lines with the
same ResourceName, the last line in the file is used.
Any whitespace character before or after the name or colon in a
ResourceSpec are ignored. To allow a Value to begin with whitespace,
the two-character sequence ``\space'' (backslash followed by space)
is recognized and replaced by a space character, and the two-
character sequence ``\tab'' (backslash followed by horizontal tab) is
recognized and replaced by a horizontal tab character. To allow a
Value to contain embedded newline characters, the two-character
sequence ``\n'' is recognized and replaced by a newline character.
To allow a Value to be broken across multiple lines in a text file,
the two-character sequence ``\newline'' (backslash followed by
newline) is recognized and removed from the value. To allow a Value
to contain arbitrary character codes, the four-character sequence
``\nnn'', where each n is a digit character in the range of
``0''-``7'', is recognized and replaced with a single byte that
contains the octal value specified by the sequence. Finally, the
two-character sequence ``\\'' is recognized and replaced with a
single backslash.
When an application looks for the value of a resource, it specifies a
complete path in the hierarchy, with both class and instance names.
However, resource values are usually given with only partially
specified names and classes, using pattern matching constructs. An
asterisk (*) is a loose binding and is used to represent any number
of intervening components, including none. A period (.) is a tight
binding and is used to separate immediately adjacent components. A
question mark (?) is used to match any single component name or
class. A database entry cannot end in a loose binding; the final
component (which cannot be "?") must be specified. The lookup
algorithm searches the resource database for the entry that most
closely matches (is most specific for) the full name and class being
queried. When more than one database entry matches the full name and
class, precedence rules are used to select just one.
The full name and class are scanned from left to right (from highest
level in the hierarchy to lowest), one component at a time. At each
level, the corresponding component and/or binding of each matching
entry is determined, and these matching components and bindings are
compared according to precedence rules. Each of the rules is applied
at each level, before moving to the next level, until a rule selects
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a single entry over all others. The rules (in order of precedence)
are:
1. An entry that contains a matching component (whether name,
class, or "?") takes precedence over entries that elide the
level (that is, entries that match the level in a loose
binding).
2. An entry with a matching name takes precedence over both entries
with a matching class and entries that match using "?". An
entry with a matching class takes precedence over entries that
match using "?".
3. An entry preceded by a tight binding takes precedence over
entries preceded by a loose binding.
Programs based on the X Tookit Intrinsics obtain resources from the
following sources (other programs usually support some subset of
these sources):
RESOURCEMANAGER root window property
Any global resources that should be available to clients on
all machines should be stored in the RESOURCE_MANAGER
property on the root window of the first screen using the
xrdb program. This is frequently taken care of when the user
starts up X through the display manager or xinit.
SCREENRESOURCES root window property
Any resources specific to a given screen (e.g. colors) that
should be available to clients on all machines should be
stored in the SCREEN_RESOURCES property on the root window of
that screen. The xrdb program will sort resources
automatically and place them in RESOURCE_MANAGER or
SCREEN_RESOURCES, as appropriate.
application-specific files
Directories named by the environment variable
XUSERFILESEARCHPATH or the environment variable XAPPLRESDIR,
plus directories in a standard place (usually under
/usr/lib/X11/, but this can be overridden with the
XFILESEARCHPATH environment variable) are searched for for
application-specific resources. For example, application
default resources are usually kept in /usr/lib/X11/app-
defaults/. See the X Toolkit Intrinsics - C Language
Interface manual for details.
XENVIRONMENT
Any user- and machine-specific resources may be specified by
setting the XENVIRONMENT environment variable to the name of
a resource file to be loaded by all applications. If this
variable is not defined, a file named $HOME/.Xdefaults-
hostname is looked for instead, where hostname is the name of
the host where the application is executing.
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X(1) X11 5.4R3.00 X(1)
-xrm resourcestring
Resources can also be specified from the command line. The
resourcestring is a single resource name and value as shown
above. Note that if the string contains characters
interpreted by the shell (e.g., asterisk), they must be
quoted. Any number of -xrm arguments may be given on the
command line.
Program resources are organized into groups called classes, so that
collections of individual resources (each of which are called
instances) can be set all at once. By convention, the instance name
of a resource begins with a lowercase letter and class name with an
upper case letter. Multiple word resources are concatenated with the
first letter of the succeeding words capitalized. Applications
written with the X Toolkit Intrinsics will have at least the
following resources:
background (class Background)
This resource specifies the color to use for the window
background.
borderWidth (class BorderWidth)
This resource specifies the width in pixels of the window
border.
borderColor (class BorderColor)
This resource specifies the color to use for the window
border.
Most applications using the X Toolkit Intrinsics also have the
resource foreground (class Foreground), specifying the color to use
for text and graphics within the window.
By combining class and instance specifications, application
preferences can be set quickly and easily. Users of color displays
will frequently want to set Background and Foreground classes to
particular defaults. Specific color instances such as text cursors
can then be overridden without having to define all of the related
resources. For example,
bitmap*Dashed: off
XTerm*cursorColor: gold
XTerm*multiScroll: on
XTerm*jumpScroll: on
XTerm*reverseWrap: on
XTerm*curses: on
XTerm*Font: 6x10
XTerm*scrollBar: on
XTerm*scrollbar*thickness: 5
XTerm*multiClickTime: 500
XTerm*charClass: 33:48,37:48,45-47:48,64:48
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XTerm*cutNewline: off
XTerm*cutToBeginningOfLine: off
XTerm*titeInhibit: on
XTerm*ttyModes: intr ^c erase ^? kill ^u
XLoad*Background: gold
XLoad*Foreground: red
XLoad*highlight: black
XLoad*borderWidth: 0
emacs*Geometry: 80x65-0-0
emacs*Background: rgb:5b/76/86
emacs*Foreground: white
emacs*Cursor: white
emacs*BorderColor: white
emacs*Font: 6x10
xmag*geometry: -0-0
xmag*borderColor: white
If these resources were stored in a file called .Xresources in your
home directory, they could be added to any existing resources in the
server with the following command:
% xrdb -merge $HOME/.Xresources
This is frequently how user-friendly startup scripts merge user-
specific defaults into any site-wide defaults. All sites are
encouraged to set up convenient ways of automatically loading
resources. See the Xlib manual section Resource Manager Functions for
more information.
EXAMPLES
The following is a collection of sample command lines for some of the
more frequently used commands. For more information on a particular
command, please refer to that command's manual page.
% xrdb $HOME/.Xresources
% xmodmap -e "keysym BackSpace = Delete"
% mkfontdir /usr/local/lib/X11/otherfonts
% xset fp+ /usr/local/lib/X11/otherfonts
% xmodmap $HOME/.keymap.km
% xsetroot -solid 'rgbi:.8/.8/.8'
% xset b 100 400 c 50 s 1800 r on
% xset q
% twm
% xmag
% xclock -geometry 48x48-0+0 -bg blue -fg white
% xeyes -geometry 48x48-48+0
% xbiff -update 20
% xlsfonts '*helvetica*'
% xwininfo -root
% xdpyinfo -display joesworkstation:0
% xhost -joesworkstation
% xrefresh
% xwd | xwud
% bitmap companylogo.bm 32x32
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% xcalc -bg blue -fg magenta
% xterm -geometry 80x66-0-0 -name myxterm $*
% xon filesysmachine xload
DIAGNOSTICS
A wide variety of error messages are generated from various programs.
The default error handler in Xlib (also used by many toolkits) uses
standard resources to construct diagnostic messages when errors
occur. The defaults for these messages are usually stored in
/usr/lib/X11/XErrorDB. If this file is not present, error messages
will be rather terse and cryptic.
When the X Toolkit Intrinsics encounter errors converting resource
strings to the appropriate internal format, no error messages are
usually printed. This is convenient when it is desirable to have one
set of resources across a variety of displays (e.g. color vs.
monochrome, lots of fonts vs. very few, etc.), although it can pose
problems for trying to determine why an application might be failing.
This behavior can be overridden by the setting the
StringConversionsWarning resource.
To force the X Toolkit Intrinsics to always print string conversion
error messages, the following resource should be placed in the file
that gets loaded onto the RESOURCE_MANAGER property using the xrdb
program (frequently called .Xresources or .Xres in the user's home
directory):
*StringConversionWarnings: on
To have conversion messages printed for just a particular
application, the appropriate instance name can be placed before the
asterisk:
xterm*StringConversionWarnings: on
SEE ALSO
XConsortium(1), XStandards(1), Xsecurity(1), appres(1), auto_box(1),
bdftopcf(1), beach_ball(1), bitmap(1), editres(1), fs(1), fsinfo(1),
fslsfonts(1), fstobdf(1), ico(1), imake(1), listres(1), lndir(1),
makedepend(1), maze(1), mkdirhier(1), mkfontdir(1), oclock(1),
plbpex(1), puzzle(1), resize(1), showfont(1), showrgb(1), twm(1),
viewres(1), x11perf(1), x11perfcomp(1), xauth(1), xbiff(1), xcalc(1),
xclipboard(1), xclock(1), xcmsdb(1), xcmstest(1), xconsole(1),
xcutsel(1), xditview(1), xdm(1), xdpr(1), xdpyinfo(1), xedit(1),
xev(1), xeyes(1), xfd(1), xfontsel(1), xgas(1), xgc(1), xhost(1),
xinit(1), xkill(1), xload(1), xlogo(1), xlsatoms(1), xlsclients(1),
xlsfonts(1), xmag(1), xman(1), xmh(1), xmkmf(1), xmodmap(1), xon(1),
xpr(1), xprop(1), xrdb(1), xrefresh(1), xset(1), xsetroot(1),
xstdcmap(1), xterm(1), xwd(1), xwininfo(1), xwud(1), Xserver(1),
Xdec(1), XmacII(1), Xmips(1), Xqdss(1), Xqvss(1), Xsun(1), X386(1),
kbd_mode(1), Xlib - C Language X Interface, and X Toolkit Intrinsics
- C Language Interface
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COPYRIGHT
The following copyright and permission notice outlines the rights and
restrictions covering most parts of the core distribution of the X
Window System from MIT. Other parts have additional or different
copyrights and permissions; see the individual source files.
Copyright 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991 by the
Massachusetts Institute of Technology.
Permission to use, copy, modify, distribute, and sell this software
and its documentation for any purpose is hereby granted without fee,
provided that the above copyright notice appear in all copies and
that both that copyright notice and this permission notice appear in
supporting documentation, and that the name of MIT not be used in
advertising or publicity pertaining to distribution of the software
without specific, written prior permission. MIT makes no
representations about the suitability of this software for any
purpose. It is provided "as is" without express or implied warranty.
TRADEMARKS
X Window System is a trademark of MIT.
AUTHORS
A cast of thousands, literally. The MIT Release 5 distribution is
brought to you by the MIT X Consortium. The names of all people who
made it a reality will be found in the individual documents and
source files. The staff members at MIT responsible for this release
are: Donna Converse (MIT X Consortium), Stephen Gildea (MIT X
Consortium), Susan Hardy (MIT X Consortium), Jay Hersh (MIT X
Consortium), Keith Packard (MIT X Consortium), David Sternlicht (MIT
X Consortium), Bob Scheifler (MIT X Consortium), and Ralph Swick
(Digital/MIT Project Athena).
Licensed material--property of copyright holder(s) 19