X(1X)X(1X)NAMEX - a portable, network-transparent window system
SYNOPSIS
The X Window System is a network transparent window system which runs
on a wide range of computing and graphics machines. It should be rela‐
tively straightforward to build the X Consortium 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 refer‐
ring to this software:
X
X Window System
X Version 11
X Window System, Version 11
X11
X Window System is a trademark of X Consortium, Inc.
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: This option specifies the
name of the X server to use. This option specifies the initial size
and location of the window. Either option specifies the color to use
for the window background. Either option specifies the color to use
for the window border. Either option specifies the width in pixels of
the window border. Either option specifies the color to use for text
or graphics. Either option specifies the font to use for displaying
text. This option indicates that the user would prefer that the appli‐
cation'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. 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 appli‐
cation, without resorting to creating links to alter the executable
file name. Either option indicates that the program should simulate
reverse video if possible, often by swapping the foreground and back‐
ground colors. Not all programs honor this or implement it correctly.
It is usually only used on monochrome displays. This option indicates
that the program should not simulate reverse video. This is used to
override any defaults since reverse video does not always work prop‐
erly. This option specifies the timeout in milliseconds within which
two communicating applications must respond to one another for a selec‐
tion request. This option indicates that requests to the X server
should be sent synchronously, instead of asynchronously. Since Xlib
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. 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. This
option specifies the language, territory, and codeset for use in
resolving resource and other filenames. This option specifies a
resource name and value to override any defaults. It is also very use‐
ful for setting resources that do not have explicit command line argu‐
ments.
DESCRIPTIONX Window System servers run on computers with bitmap displays. The
server distributes user input to and accepts output requests from vari‐
ous client programs through a variety of different interprocess commu‐
nication 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 dif‐
ferent 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 explana‐
tion 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 X Consortium distribution include: a terminal emulator
(xterm), a window manager (twm), a display manager (xdm), a console re‐
direct program (xconsole), a mail interface (xmh), a bitmap editor
(bitmap), resource listing/manipulation tools (appres, editres), access
control programs (xauth, xhost, and iceauth), user preference setting
programs (xrdb, xcmsdb, xset, xsetroot, xstdcmap, and xmodmap), clocks
(xclock and oclock), a font displayer (xfd), utilities for listing
information about fonts, windows, and displays (xlsfonts, xwininfo,
xlsclients, xdpyinfo, xlsatoms, and xprop), screen image manipulation
utilities (xwd, xwud, and xmag), a performance measurement utility
(x11perf), a font compiler (bdftopcf), a font server and related utili‐
ties (xfs, fsinfo, fslsfonts, fstobdf), an X Image Extension exerciser
(xieperf), a display server and related utilities (Xserver, rgb,
mkfontdir), remote execution utilities (rstart and xon), a clipboard
manager (xclipboard), a keyboard description compiler (xkbcomp), a
utility to terminate clients (xkill), and a utility to cause part or
all of the screen to be redrawn (xrefresh).
Many other utilities, window managers, games, toolkits, and so forth.
are included as user-contributed software in the X Consortium distribu‐
tion, 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 whether or not you use other
window systems in addition to X. 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 suc‐
cessfully logged in, xdm will start up your X environment. By default,
if you have an executable file named 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, and
so forth.). Your site administrator can provide details.
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 should
connect to the server and which screen it should use by default (on
displays with multiple monitors): The hostname specifies the name of
the machine to which the display is physically connected. If the host‐
name is not given, the most efficient way of communicating to a server
on the same machine will be used. The phrase "display" is usually used
to refer to collection of monitors that share a common keyboard and
pointer (mouse, tablet, and so forth.). Most workstations tend to only
have one keyboard, and therefore, only one display. Larger, multi-user
systems, however, 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. Some displays share a single key‐
board and pointer among two or more monitors. Since each monitor has
its own set of windows, each screen is assigned a screen number (begin‐
ning at 0) when the X server for that display is started. If the
screen number is not given, 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 will 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 dis‐
playname 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 communica‐
tions channels (network byte streams, shared memory, and so forth.).
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 gener‐
ally support the following types of connections: 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. 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: x.org:0, expo:0, 198.112.45.11:0, bigmachine:1,
and hydra:0.1. 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 pro‐
vided in Release 6 are:
Host Access Simple host-based access control.
MIT-MAGIC-COOKIE-1 Shared plain-text "cookies".
MIT-KERBEROS-5 Kerberos Version 5 user-to-user.
xdm initializes access control for the server and also places autho‐
rization 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 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, you never really
have to worry about authorization files, the system should work cor‐
rectly 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 envi‐
ronments, this level of security is 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(1X) manual
page.
GEOMETRY SPECIFICATIONS
One of the advantages of using window systems instead of hardwired ter‐
minals is that applications do not have to be restricted to a particu‐
lar 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: The left
edge of the window is to be placed XOFF pixels in from the left edge of
the screen (that is, 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. 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: The top edge of the window is to be
YOFF pixels below the top edge of the screen (that is, 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. 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: upper
left hand corner. upper right hand corner. lower right hand corner.
lower left hand corner.
In the following examples, a terminal emulator is placed in roughly the
center of the screen and a load average monitor, mailbox, and clock are
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 geom‐
etry specifications as given, others may choose to ignore them (requir‐
ing 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 X Consortium
distribution comes with a window manager named twm which supports over‐
lapping windows, popup menus, point-and-click or click-to-type input
models, title bars, nice icons (and an icon manager for those who do
not like separate icon windows).
See the user-contributed software in the X Consortium 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, bold‐
ness, 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 signifi‐
cantly better results than scaling from bitmap fonts.
An X server can obtain fonts from individual files stored in directo‐
ries 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 the server's
machine, not on the application's.
Bitmap font files are usually created by compiling a textual font
description into binary form, using bdftopcf. Font databases are cre‐
ated 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:
-*-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 con‐
taining the first zero is for the pixel size; replace it with a spe‐
cific 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 sepa‐
rator.
Examples: tcp/x.org:7100, tcp/198.112.45.11:7100/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, decnet/44.70::font$special/sym‐
bols.
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 numeri‐
cal 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 com‐
monly stored in the file <XRoot>/lib/X11/rgb.txt, where <XRoot> is
replaced by the root of the X11 install tree.
A numerical color specification consists of a color space name and a
set of values in the following syntax:
<color_space_name>:<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 sup‐
ported, but its continued use is not encouraged. The syntax is an ini‐
tial sharp sign character followed by a numeric specification, in one
of the following formats:
#RGB (4 bits each)
#RRGGBB (8 bits each)
#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 possi‐
bly containing a decimal point, and an optional exponent field contain‐
ing an E or e followed by a possibly signed integer string.
The standard device-independent string specifications have the follow‐
ing 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 refer‐
ence manual.
KEYBOARDS
The X keyboard model is broken into two layers: server-specific codes
(called keycodes) which represent the physical keys, and server-inde‐
pendent symbols (called keysyms) which represent the letters or words
that appear on the keys. Two tables are kept in the server for convert‐
ing keycodes to keysyms: 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
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 con‐
tains 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. 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 ta‐
ble 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 lan‐
guage 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 con‐
tains the third and fourth keysyms. Within each group, if the first
element is alphabetic and 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 mod‐
ifier 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.
RESOURCES
To make the tailoring of applications to personal preferences easier, X
provides a mechanism for storing default values for program resources
(for example, background color, window title, and so forth.) 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
(for example, Bitmap or Emacs) although some programs that begin with
the letter “x” also capitalize the second letter for historical rea‐
sons.
The precise syntax for resources is:
ResourceLine = Comment | IncludeFile | ResourceSpec |
<empty line>
Comment = "!" {<any character except null or new‐
line>}
IncludeFile = "#" WhiteSpace "include" WhiteSpace File‐
Name WhiteSpace
FileName = <valid filename for operating system>
ResourceSpec = WhiteSpace ResourceName WhiteSpace ":"
WhiteSpace Value
ResourceName = [Binding] {Component Binding} Component‐
Name
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 con‐
tents 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 direc‐
tory 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 recog‐
nized and replaced by a newline character. To allow a Value to be bro‐
ken 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 speci‐
fied names and classes, using pattern matching constructs. An asterisk
(*) is a loose binding and is used to represent any number of interven‐
ing 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 a
single entry over all others. The rules (in order of precedence) are:
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). 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 "?". An entry preceded by a
tight binding takes precedence over entries preceded by a loose bind‐
ing.
Programs based on the X Tookit Intrinsics obtain resources from the
following sources (other programs usually support some subset of these
sources): 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 fre‐
quently taken care of when the user starts up X through the display
manager. Any resources specific to a given screen (for example, col‐
ors) 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. Directo‐
ries named by the environment variable XUSERFILESEARCHPATH or the envi‐
ronment variable XAPPLRESDIR (which names a single directory and should
end with a '/' on POSIX systems), plus directories in a standard place
(usually under <XRoot>/lib/X11/, but this can be overridden with the
XFILESEARCHPATH environment variable) are searched for application-spe‐
cific resources. For example, application default resources are usually
kept in <XRoot>/lib/X11/app-defaults/. See the X Toolkit Intrinsics --
C Language Interface manual for details. Any user- and machine-spe‐
cific resources may be specified by setting the XENVIRONMENT environ‐
ment variable to the name of a resource file to be loaded by all appli‐
cations. If this variable is not defined, a file named $HOME/.Xde‐
faults-hostname is looked for instead, where hostname is the name of
the host where the application is executing. 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 con‐
tains characters interpreted by the shell (for example, asterisk), they
must be quoted. Any number of -xrm arguments may be given on the com‐
mand 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:
This resource specifies the color to use for the window background.
This resource specifies the width in pixels of the window border. 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
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 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-spe‐
cific 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
% 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
<XRoot>/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 usu‐
ally printed. This is convenient when it is desirable to have one set
of resources across a variety of displays (for example, color vs. mono‐
chrome, lots of fonts vs. very few, and so forth.), although it can
pose problems for trying to determine why an application might be fail‐
ing. This behavior can be overridden by the setting the StringConver‐
sionsWarning 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 pro‐
gram (frequently called or 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
TRADEMARKSX Window System is a trademark of X Consortium, Inc. Fresco is a regis‐
tered trademark of X Consortium, Inc.
SEE ALSOXConsortium(1X), XStandards(1X), XSecurity(1X), appres(1X),
bdftopcf(1X), bitmap(1X), editres(1X), fsinfo(1X), fslsfonts(1X),
fstobdf(1X), ico(1X), imake(1X), makedepend(1X), maze(1X),
mkdirhier(1X), mkfontdir(1X), oclock(1X), puzzle(1X), resize(1X),
rstart(1X), showfont(1X), showrgb(1X), twm(1X), viewres(1X),
x11perf(1X), x11perfcomp(1X), xauth(1X), xbiff(1X), xcalc(1X), xclip‐
board(1X), xclock(1X), xcmsdb(1X), xconsole(1X), xcutsel(1X), xdm(1X),
xdpr(1X), xdpyinfo(1X), xedit(1X), xev(1X), xeyes(1X), xfd(1X),
xfs(1X), xfontsel(1X), xgc(1X), xhost(1X), xieperf(1X), xkbcomp(1X),
xkill(1X), xlogo(1X), xlsatoms(1X), xlsclients(1X), xlsfonts(1X),
xmag(1X), xmh(1X), xmkmf(1X), xmodmap(1X), xon(1X), xpr(1X), xprop(1X),
xrdb(1X), xrefresh(1X), xset(1X), xsetroot(1X), xstdcmap(1X),
xterm(1X), xwd(1X), xwininfo(1X), xwud(1X), Xserver(1X), Xdec(1X), Xlib
-- C Language X Interface, and X Toolkit Intrinsics -- C Language
Interface
AUTHORS
A cast of thousands, literally. The Release 6 distribution is brought
to you by X Consortium, Inc. The names of all people who made it a
reality will be found in the individual documents and source files.
The staff members at the X Consortium responsible for this release are:
Donna Converse, Gary Cutbill, Stephen Gildea, Jay Hersh, Kaleb Keith‐
ley, Matt Landau, Ralph Mor, Janet O'Halloran, Bob Scheifler, Ralph
Swick, and Dave Wiggins.
The X Window System standard was originally developed at the Laboratory
for Computer Science at the Massachusetts Institute of Technology, and
all rights thereto were assigned to the X Consortium on January 1,
1994.
X(1X)