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X(1X)
X11R6
NAME
X - 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 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.
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 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 does
not 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 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 do not
have explicit command line arguments.
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 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.
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.
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, 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):
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, 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.
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, 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:
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.
TCP/IP
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.
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 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 .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, 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
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:
+XOFF
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.
-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 (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.
-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.
-0-0
lower right hand corner.
+0-0
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 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.
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 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.
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/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.
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 <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.
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 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 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.
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 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 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 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):
RESOURCE_MANAGER 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.
SCREEN_RESOURCES root window property
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.
application-specific files
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.
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.
-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
(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:
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
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
% 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 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 .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
TRADEMARKS
X Window System is a trademark of X Consortium, Inc. Fresco is a registered
trademark of X Consortium, Inc.
SEE ALSO
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
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 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.
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