X - a portable, network-transparent window system
The X Window System is a network transparent window system
which runs on a wide range of computing and graphics
machines. It should be relatively 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 referring 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.
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 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. 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.
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. 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 properly. This option specifies the timeout in milliseconds
within which two communicating applications must
respond to one another for a selection 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 useful for setting resources that do not have
explicit command line arguments.
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 X Consortium distribution
include: a terminal emulator (xterm), a window manager
(twm), a display manager (xdm), a console redirect 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 utilities
(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 distribution, or are available using
anonymous ftp on the Internet. See your site administrator
for details.
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 successfully
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.
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 hostname
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 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, 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 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,
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
generally 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.
An X server can use several types of access control.
Mechanisms provided 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 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 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 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 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 [Toc] [Back] One of the advantages of using window systems instead of
hardwired terminals is that applications do not 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: 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 &
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 X Consortium 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 do not like separate icon windows).
See the user-contributed software in the X Consortium distribution
for other popular window managers.
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 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 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:
-*-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.
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/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/symbols.
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
<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 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)
#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.
The X keyboard model is broken into two layers: serverspecific
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: 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 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. 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 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.
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 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 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 twocharacter
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 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 binding.
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 frequently
taken care of when the user starts up X through
the display manager. Any resources specific to a given
screen (for example, 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. Directories named by the environment variable
XUSERFILESEARCHPATH or the environment 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-specific 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-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.
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 (for example, 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: 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-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.
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
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 usually printed. This is convenient
when it is desirable to have one set of resources across a
variety of displays (for example, color vs. monochrome,
lots of fonts vs. very few, and so forth.), 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 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
X Window System is a trademark of X Consortium, Inc.
Fresco is a registered trademark of X Consortium, Inc.
XConsortium(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), xclipboard(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
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 Keithley, 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)
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