NAME

X − a portable, network−transparent window system

SYNOPSIS

X is a network−transparent window system developed at MIT that runs on a wide range of computing and graphics machines. 

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

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 interprocess communication channels.  Although the most common case is for the client programs to run 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. 

A wide variety of application programs use X.  See Using DeltaWINDOWS for more information about these programs and references to other documents. 

STARTING UP

Before you can use X applications, the X server and an initial client process must have been started.  See your site administrator for details. 

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.  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) for starting up your initial clients (such as terminal emulators, clocks, a window manager, user settings for things like the background, the speed of the pointer, etc.).  Your site administrator can provide details. 

DISPLAY NAMES

From the user’s perspective, 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), as follows:

hostname
This part of the display name specifies the hostname 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 term display usually refers to a collection of monitors that share a common keyboard and pointer (e.g., mouse, tablet).  Some systems have only one keyboard and, therefore, only one display.  Multiuser systems may 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 part of 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. 

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 in to another machine on a network, you will need to set DISPLAY by hand to point to your display.  For example:

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
remsh myhost /bin/X11/xterm −display myws:0 −ls </dev/null &

X servers listen for connections on a variety of communications channels (e.g., network byte streams, shared memory).  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.  The X server supports the following types of connections:

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.  Examples include:

expo.lcs.mit.edu:0
expo:0
18.30.0.212:0
bigmachine:1, and hydra:0.1. 

ACCESS CONTROL

An X server can use several types of access control.  Mechanisms provided in Release 5 are:

    Host AccessSimple host-based access control.
    MIT-MAGIC-COOKIE-1Shared plain-text "cookies".
    XDM-AUTHORIZATION-1Secure DES based private-keys.
    SUN-DES-1Based on Sun’s secure rpc system.

Xdm initializes access control for the server, and also places authorization information in a file accessible to the user.  Normally, the list of hosts from which connections are always accepted should be empty, so that only clients with are explicitly authorized can connect to the display.  When you add entries to the host list (with xhost), the server no longer performs any authorization on connections from those machines.  Be careful with this. 

The file from which Xlib extracts authorization data can be specified with the environment variable XAUTHORITY, and defaults to the file .Xauthority in the home directory.  xdm uses $HOME/.Xauthority and will create it or merge in authorization records if it already exists when a user logs in. 

If you use several machines, and share a common home directory across all of the machines by means of a network file system, then you never really have to worry about authorization files, the system should work correctly by default.  Otherwise, as the authorization files are machine-independent, you can simply copy the files to share them.  To manage authorization files, use xauth.  This program allows you to extract records and insert them into other files.  Using this, you can send authorization to remote machines when you login, if the remote machine does not share a common home directory with your local machine.  Note that authorization information transmitted “in the clear” through a network file system or using ftp or rcp can be “stolen” by a network eavesdropper, and as such may enable unauthorized access.  In many environments this level of security is not a concern, but if it is, you need to know the exact semantics of the particular authorization data to know if this is actually a problem. 

For more information on access control, see the Xsecurity manual page. 

GEOMETRY SPECIFICATIONS

One of the advantages of using window systems instead of hardwired terminals is that applications 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 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 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 the top or bottom edges of the screen, respectively.  Both types of offsets are measured from the indicated edge of the screen to the corresponding edge of the window.  The X offset may be specified in the following ways:

+XOFF
The left edge of the window is to be placed XOFF pixels in from the left edge of the screen (i.e., the X coordinate of the window’s origin will be XOFF).  XOFF may be negative, in which case the window’s left edge will be off the screen. 

−XOFF
The right edge of the window is to be placed XOFF pixels in from the right edge of the screen.  XOFF may be negative, in which case the window’s right edge will be off the screen. 

The Y offset has similar meanings:

+YOFF
The top edge of the window is to be YOFF pixels below the top edge of the screen (i.e., the Y coordinate of the window’s origin will be YOFF).  YOFF may be negative, in which case the window’s top edge will be off the screen. 

−YOFF
The bottom edge of the window is to be YOFF pixels above the bottom edge of the screen.  YOFF may be negative, in which case the window’s bottom edge will be off the screen. 

Offsets must be given as pairs; in other words, 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+0upper left hand corner
−0+0upper right hand corner
−0−0lower right hand corner
+0−0lower left hand corner

In the following examples, a terminal emulator will be placed in roughly the center of the screen, and a load average monitor, mailbox, and clock will be placed in the upper right−hand corner:

xterm −fn 6x10 −geometry 80x24+30+200 &
xclock −geometry 48x48−0+0 &
xload −geometry 48x48−96+0 &
xbiff −geometry 48x48−48+0 &

It is possible to combine the positive and negative signs to control the geometry.  For example, the following command attempts to place the right edge of the window at a location that is 100 pixels in from the right side of the screen and the top edge 50 pixels down from the top of the screen:

xterm −geometry 80x24−−100+−50 &

Some window managers, such as twm and mwm (see the following discussion of window managers), may override geometry requests and place windows at a location that only approximates the requested position. 

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 user interfaces can be built.  X 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). 

Other window managers that are available:

mwm
This is the OSF/Motif window manager from The Open Software Foundation. mwm is available on the Motorola OSF/Motif installation. 

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 typeface are called families; the variations within a family are usually roman, bold, italic, bold italic, oblique, and bold oblique. 

Sets of font families of the same resolution (usually measured in dots per inch) are further grouped into directories (so named because they were initially stored in file system directories).  Each directory contains a database which lists the name of the font and information on how to find the font.  The server uses these databases to translate font names (which have nothing to do with file names) into font data. 

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 the commonly used font directories, 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.  If your display is an X terminal, see the X terminal documentation for information about font availability. 

For NCD X terminals, the corresponding font paths are:

/usr/lib/X11/ncd/fonts/misc
/usr/lib/X11/ncd/fonts/75dpi
/usr/lib/X11/ncd/fonts/100dpi

Font databases are created by running the mkfontdir program in the directory containing the source or compiled versions of the fonts (in both compressed and uncompressed formats).  Whenever fonts are added to a directory, rerun mkfontdir 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, the following commands could be used to add a font to a private directory:

cp newfont.snf $HOME/myfonts
mkfontdir $HOME/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 long because they contain all 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

could be abbreviated as:

−∗−courier−medium−r−normal−−∗−100−∗−∗−∗−∗−∗−∗

or, more tersely (but less accurately):

∗−courier−medium−r−normal−−∗−100−∗

Because the shell also has special meanings for the asterisk (∗) and the question mark (?), wildcarded font names should be quoted:

xlsfonts −fn ’courier−medium−r−normal−−∗−100−∗’

If more than one font in a given directory in the font path matches a wildcarded font name, the choice of which font to return is left to the server.  However, if fonts from more than one directory match a name, the returned font is always from the first such directory in the font path.  The example given above matches fonts in both the 75dpi and 100dpi directories; if the 75dpi directory is ahead of the 100dpi directory in the font path, the 75dpi version is used. 

COLOR NAMES

Most applications provide ways of tailoring 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 for NCD X terminals is stored in the file /usr/lib/X11/ncd/rgb.txt. 

Color names are case-insensitive, meaning that red, Red, and RED all refer to the same color.  In addition, separating spaces in color names are ignored.  For example, Medium Slate Blue is equivalent to mediumslateblue. 

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:

    blackrgb:0/0/0
    redrgb:ffff/0/0
    greenrgb:0/ffff/0
    bluergb:0/0/ffff
    yellowrgb:ffff/ffff/0
    magentargb:ffff/0/ffff
    cyanrgb:0/ffff/ffff
    whitergb: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. 

KEYS

The X keyboard model contains two layers:  server−specific codes (called keycodes) which represent the physical keys, and server−independent symbols (called keysyms) that represent the letters or words that appear on the keys.  The server keeps two tables for converting keycodes to keysyms:

modifier list
Some keys (such as SHIFT, CTRL, and CAPS LOCK) are known as modifiers and are used to select different symbols that are attached to a single key.  For example, SHIFT−a generates a capital A, and CTRL−l generates a formfeed 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 initially set this list to contain the various SHIFT, CTRL, 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 each modifier.  This table is initialized by the server to correspond to normal typewriter conventions.  The exact semantics of how the table is interpreted to produce keysyms depends on the particular program, libraries, and language input method used, but the following conventions for the first four keysyms in each row are generally adhered to:

The first four elements of the list are split into two groups of keysyms.  Group 1 contains the first and second keysyms; Group 2 contains the third and fourth keysyms.  Within each group, if the first element is alphabetic and the the second element is the special keysym NoSymbol, then the group is treated as equivalent to a group in which the first element is the lowercase letter and the second element is the uppercase letter. 

Switching between groups is controlled by the keysym named MODE SWITCH, by attaching that keysym to some key and attaching that key to any one of the modifiers Mod1 through Mod5.  This modifier is called the “group modifier.” Group 1 is used when the group modifier is off, and Group 2 is used when the group modifier is on. 

Within a group, the modifier state determines which keysym to use.  The first keysym is used when the Shift and Lock modifiers are off.  The second keysym is used when the Shift modifier is on, when the Lock modifier is on and the second keysym is uppercase alphabetic, or when the Lock modifier is on and is interpreted as ShiftLock.  Otherwise, when the Lock modifier is on and is interpreted as CapsLock, the state of the Shift modifier is applied first to select a keysym; but if that keysym is lowercase alphabetic, then the corresponding uppercase keysym is used instead. 

OPTIONS

Most X programs attempt to use the same names for command line options and arguments.  All applications written with the X Toolkit Intrinsics automatically accept the following options:

−display display
This specifies the name of the X server to use.

−geometry geometry
This specifies the initial size and location of the window.

−bgcolor, −background color
Either option specifies the color to use for the window background.

−bdcolor, −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.

−fgcolor, −foreground color
Either option specifies the color to use for text or graphics.

−fnfont, −font font
Either option specifies the font to use for displaying text.

−iconic
This indicates that the application’s windows initially not be visible, as if the windows had to be immediately iconified by the user. Window managers may choose not to honor the application’s request.

−name
This 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 filename.

−rv, −reverse
This 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 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 specifies the timeout in milliseconds within which two communicating applications must respond to one another for a selection request.

−synchronous
This indicates that requests to the X server should be sent synchronously instead of asynchronously. Since the X library (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 specifies the title to be used for this window. This information is sometimes used by a window manager to provide a header identifying the window.

−xnllanguage language[_territory][.codeset]
This specifies the language, territory, and codeset for use in resolving resources and other filenames.

−xrm resourcestring
This 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.

RESOURCES

To make the tailoring of applications to personal preferences easier, X provides a mechanism for storing default values for program resources (e.g., background color, window title).  Resources are specified as strings that are read in from various places when an application is run.  Program components are named in a hierarchical fashion, with each node in the hierarchy identified by a class and an instance name.  At the top level is the class and instance name of the application itself.  By convention, the class name of the application is the same as the program name, but with  the first letter capitalized (e.g. Bitmap or Emacs) although some programs that begin with the letter “x” also capitalize the second letter for historical reasons. 

The precise syntax for resources is:

ResourceLine=Comment | IncludeFile | ResourceSpec | <empty line>
Comment="!" {<any character except null or newline>}
IncludeFile="#" WhiteSpace "include" WhiteSpace FileName WhiteSpace
FileName=<valid filename for operating system>
ResourceSpec=WhiteSpace ResourceName WhiteSpace ":" WhiteSpace Value
ResourceName=[Binding] {Component Binding} ComponentName
Binding="." | "∗"
WhiteSpace={<space> | <horizontal tab>}
Component="?" | ComponentName
ComponentName=NameChar {NameChar}
NameChar="a"−"z" | "A"−"Z" | "0"−"9" | "_" | "-"
Value={<any character except null or unescaped newline>}

Elements separated by vertical bar (|) are alternatives.  Curly braces ({...}) indicate zero or more repetitions of the enclosed elements.  Square brackets ([...]) indicate that the enclosed element is optional.  Quotes ("...") are used around literal characters. 

IncludeFile lines are interpreted by replacing the line with the 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 (e.g. colors) that should be available to clients on all machines should be stored in the SCREEN_RESOURCES property on the root window of that screen. The xrdb program will sort resources automatically and place them in RESOURCE_MANAGER or SCREEN_RESOURCES, as appropriate. 

application−specific files
Directories named by the environment variable XUSERFILESEARCHPATH or the environment variable XAPPLRESDIR, plus directories in a standard place (usually under /usr/lib/X11/, but this can be overridden with the XFILESEARCHPATH environment variable) are searched for for application-specific resources. For example, application default resources are usually kept in /usr/lib/X11/app-defaults/.

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, the X Toolkit looks for a file named $HOME/.Xdefaults−hostname, where hostname is the name of the host where the application is executing. 

−xrm resource string
Resources can also be specified from the from the command line. The resource string is a single resource name and value as shown above.  Note that if the string contains characters interpreted by the shell (e.g., asterisk), they must be quoted.  Any number of these 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 is called an instance) can be set all at once.  By convention, the instance name of a resource begins with a lowercase letter and the class name with an uppercase 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)
specifies the color to use for the window background

borderWidth (class BorderWidth)
specifies the width in pixels of the window border

borderColor (class BorderColor)
specifies the color to use for the window border

Most X Toolkit Intrinsics applications 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 start−up scripts merge user−specific defaults into any site−wide defaults.  All sites are encouraged to set up convenient ways of automatically loading resources. 

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, 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, which is also used by many toolkits, uses standard resources to construct diagnostic messages when errors occur.  The defaults for these messages are usually stored in /usr/lib/X11/XErrorDB.  If this file is not present, error messages will be terse and cryptic. 

When the X Toolkit Intrinsics encounters errors converting resource strings to the appropriate internal format, error messages are not usually printed.  This is convenient when it is desirable to have one set of resources across a variety of displays (e.g., color vs. monochrome, many fonts vs. few), although it can pose problems when trying to determine why an application might be failing.  This behavior can be overridden by setting the StringConversionWarnings resource. 

To force the 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 (this file is frequently called .Xresources, .Xres, or .Xdefaults in the user’s home directory):

∗StringConversionWarnings: on

To have conversion messages printed for a particular application, the appropriate instance name can be placed before the asterisk:

xterm∗StringConversionWarnings: on

SEE ALSO

bitmap(1), mkfontdir(1), twm(1), xauth(1), xbiff(1), xcalc(1), xdm(1), xdpyinfo(1),
xhost(1), xload(1), xlsfonts(1), xlswins(1), xmag(1), xmodmap(1), xrdb(1),
xrefresh(1), xset(1), xsetroot(1), xterm(1), xwd(1), xwininfo(1), xwud(1). 
Using DeltaWINDOWS.