14 .TH XScreenSaver 1 "02-Jan-2002 (4.00)" "X Version 11"
16 xscreensaver - extensible screen saver framework, plus locking
19 [\-display \fIhost:display.screen\fP] \
21 [\-no\-capture\-stderr] \
24 The \fIxscreensaver\fP program waits until the keyboard and mouse have been
25 idle for a period, and then runs a graphics demo chosen at random. It
26 turns off as soon as there is any mouse or keyboard activity.
28 This program can lock your terminal in order to prevent others from using it,
29 though its default mode of operation is merely to display pretty pictures on
30 your screen when it is not in use.
32 It also provides configuration and control of your monitor's power-saving
35 For the impatient, try this:
41 .BR xscreensaver-demo (1)
42 program pops up a dialog box that lets you configure the screen saver,
43 and experiment with the various display modes.
48 xscreensaver has a client-server model: the \fIxscreensaver\fP program is a
49 daemon that runs in the background; it is controlled by the foreground
50 .BR xscreensaver-demo (1)
52 .BR xscreensaver-command (1)
55 The easiest way to configure \fIxscreensaver\fP is to simply run the
56 .BR xscreensaver-demo (1)
57 program, and change the settings through the GUI. The rest of this
58 manual page describes lower level ways of changing settings.
60 Options to \fIxscreensaver\fP are stored in one of two places: in
61 a \fI.xscreensaver\fP file in your home directory; or in the X resource
62 database. If the \fI.xscreensaver\fP file exists, it overrides any settings
63 in the resource database.
65 The syntax of the \fI.xscreensaver\fP file is similar to that of
66 the \fI.Xdefaults\fP file; for example, to set the \fItimeout\fP paramter
67 in the \fI.xscreensaver\fP file, you would write the following:
71 whereas, in the \fI.Xdefaults\fP file, you would write
73 xscreensaver.timeout: 5
75 If you change a setting in the \fI.xscreensaver\fP file while xscreensaver
76 is already running, it will notice this, and reload the file. (The file will
77 be reloaded the next time the screen saver needs to take some action, such as
78 blanking or unblanking the screen, or picking a new graphics mode.)
80 If you change a setting in your X resource database, or if you want
81 xscreensaver to notice your changes immediately instead of the next time
82 it wakes up, then you will need to tell the running xscreensaver process
83 to re-initialize itself, like so:
85 xscreensaver-command -restart
87 Note that if you changed the \fI.Xdefaults\fP file, you might also need to run
92 If you want to set the system-wide defaults, then make your edits to
93 the xscreensaver app-defaults file, which should have been installed
94 when xscreensaver itself was installed. The app-defaults file will
95 usually be named /usr/lib/X11/app-defaults/XScreenSaver, but different
96 systems might keep it in a different place (for example,
97 /usr/openwin/lib/app-defaults/XScreenSaver on Solaris.)
99 When settings are changed in the Preferences dialog box (see above)
100 the current settings will be written to the \fI.xscreensaver\fP file.
101 (The \fI.Xdefaults\fP file and the app-defaults file will never be
102 written by xscreensaver itself.)
105 .B timeout\fP (class \fBTime\fP)
106 The screensaver will activate (blank the screen) after the keyboard and
107 mouse have been idle for this many minutes. Default 10 minutes.
109 .B cycle\fP (class \fBTime\fP)
110 After the screensaver has been running for this many minutes, the currently
111 running graphics-hack sub-process will be killed (with \fBSIGTERM\fP), and a
112 new one started. If this is 0, then the graphics hack will never be changed:
113 only one demo will run until the screensaver is deactivated by user activity.
116 .B lock\fP (class \fBBoolean\fP)
117 Enable locking: before the screensaver will turn off, it will require you
118 to type the password of the logged-in user (really, the person who ran
119 xscreensaver), or the root password. (\fBNote:\fP this doesn't work if the
120 screensaver is launched by
122 because it can't know the user-id of the logged-in user. See
123 the ``\fIUsing XDM(1)\fP'' section, below.
125 .B lockTimeout\fP (class \fBTime\fP)
126 If locking is enabled, this controls the length of the ``grace period''
127 between when the screensaver activates, and when the screen becomes locked.
128 For example, if this is 5, and \fI\-timeout\fP is 10, then after 10 minutes,
129 the screen would blank. If there was user activity at 12 minutes, no password
130 would be required to un-blank the screen. But, if there was user activity
131 at 15 minutes or later (that is, \fI\-lock\-timeout\fP minutes after
132 activation) then a password would be required. The default is 0, meaning
133 that if locking is enabled, then a password will be required as soon as the
136 .B passwdTimeout\fP (class \fBTime\fP)
137 If the screen is locked, then this is how many seconds the password dialog box
138 should be left on the screen before giving up (default 30 seconds.) This
139 should not be too large: the X server is grabbed for the duration that the
140 password dialog box is up (for security purposes) and leaving the server
141 grabbed for too long can cause problems.
143 .B dpmsEnabled\fP (class \fBBoolean\fP)
144 Whether power management is enabled.
146 .B dpmsStandby\fP (class \fBTime\fP)
147 If power management is enabled, how long until the monitor goes solid black.
149 .B dpmsSuspend\fP (class \fBTime\fP)
150 If power management is enabled, how long until the monitor goes into
153 .B dpmsOff\fP (class \fBTime\fP)
154 If power management is enabled, how long until the monitor powers down
155 completely. Note that these settings will have no effect unless both
156 the X server and the display hardware support power management; not
157 all do. See the \fIPower Management\fP section, below, for more
160 .B visualID\fP (class \fBVisualID\fP)
161 Specify which X visual to use by default. (Note carefully that this resource
162 is called \fBvisualID\fP, not merely \fBvisual\fP; if you set the \fBvisual\fP
163 resource instead, things will malfunction in obscure ways for obscure reasons.)
165 Legal values for the \fBVisualID\fP resource are:
169 Use the screen's default visual (the visual of the root window.)
173 Use the visual which supports the most colors. Note, however, that the
174 visual with the most colors might be a TrueColor visual, which does not
175 support colormap animation. Some programs have more interesting behavior
176 when run on PseudoColor visuals than on TrueColor.
179 Use a monochrome visual, if there is one.
182 Use a grayscale or staticgray visual, if there is one and it has more than
183 one plane (that is, it's not monochrome.)
186 Use the best of the color visuals, if there are any.
189 Use the visual that is best for OpenGL programs. (OpenGL programs have
190 somewhat different requirements than other X programs.)
193 where \fIclass\fP is one of \fBStaticGray\fP, \fBStaticColor\fP,
194 \fBTrueColor\fP, \fBGrayScale\fP, \fBPseudoColor\fP, or \fBDirectColor\fP.
195 Selects the deepest visual of the given class.
198 where \fInumber\fP (decimal or hex) is interpreted as a visual id number,
201 program; in this way you can have finer control over exactly which visual
202 gets used, for example, to select a shallower one than would otherwise
207 Note that this option specifies only the \fIdefault\fP visual that will
208 be used: the visual used may be overridden on a program-by-program basis.
209 See the description of the \fBprograms\fP resource, below.
212 .B installColormap\fP (class \fBBoolean\fP)
213 Install a private colormap while the screensaver is active, so that the
214 graphics hacks can get as many colors as possible. This is the
215 default. (This only applies when the screen's default visual is being
216 used, since non-default visuals get their own colormaps automatically.)
217 This can also be overridden on a per-hack basis: see the discussion of
218 the \fBdefault\-n\fP name in the section about the \fBprograms\fP resource.
220 .B verbose\fP (class \fBBoolean\fP)
221 Whether to print diagnostics. Default false.
223 .B timestamp\fP (class \fBBoolean\fP)
224 Whether to print the time of day along with any other diagnostic messages.
227 .B splash\fP (class \fBBoolean\fP)
228 Whether to display a splash screen at startup. Default true.
230 .B splashDuration\fP (class \fBTime\fP)
231 How long the splash screen should remain visible; default 5 seconds.
233 .B helpURL\fP (class \fBURL\fP)
234 The splash screen has a \fIHelp\fP button on it. When you press it, it will
235 display the web page indicated here in your web browser.
237 .B loadURL\fP (class \fBLoadURL\fP)
238 This is the shell command used to load a URL into your web browser.
239 The default setting will load it into Netscape if it is already running,
240 otherwise, will launch a new Netscape looking at the \fIhelpURL\fP.
242 .B demoCommand\fP (class \fBDemoCommand\fP)
243 This is the shell command run when the \fIDemo\fP button on the splash window
244 is pressed. It defaults to \fIxscreensaver\-demo\fP.
246 .B prefsCommand\fP (class \fBPrefsCommand\fP)
247 This is the shell command run when the \fIPrefs\fP button on the splash window
248 is pressed. It defaults to \fIxscreensaver\-demo\ \-prefs\fP.
250 .B nice\fP (class \fBNice\fP)
251 The sub-processes created by \fIxscreensaver\fP will be ``niced'' to this
252 level, so that they are given lower priority than other processes on the
253 system, and don't increase the load unnecessarily. The default is 10.
255 (Higher numbers mean lower priority; see
259 .B memoryLimit\fP (class \fBMemoryLimit\fP)
260 The sub-processes created by \fIxscreensaver\fP will not be allowed to
261 allocate more than this much memory (more accurately, this is the maximum
262 size their address space may become.) If any sub-process tries to allocate
265 will fail, and the process will likely exit (or safely crash) rather than
266 going forth and hogging memory.
268 The assumption here is that if one of the screenhacks is trying to use
269 a lot of memory, then something has gone wrong, and it's better to kill
270 that program than to overload the machine.
272 Default: 0, meaning "no limit." 30M is a good choice on most systems.
273 (But beware that setting this to a small value can cause OpenGL programs
274 to malfunction on certain systems.)
276 .B fade\fP (class \fBBoolean\fP)
277 If this is true, then when the screensaver activates, the current contents
278 of the screen will fade to black instead of simply winking out. This only
279 works on certain systems. A fade will also be done when switching graphics
280 hacks (when the \fIcycle\fP timer expires.) Default: true.
282 .B unfade\fP (class \fBBoolean\fP)
283 If this is true, then when the screensaver deactivates, the original contents
284 of the screen will fade in from black instead of appearing immediately. This
285 only works on certain systems, and if \fIfade\fP is true as well.
288 .B fadeSeconds\fP (class \fBTime\fP)
289 If \fIfade\fP is true, this is how long the fade will be in
290 seconds (default 3 seconds.)
292 .B fadeTicks\fP (class \fBInteger\fP)
293 If \fIfade\fP is true, this is how many times a second the colormap will
294 be changed to effect a fade. Higher numbers yield smoother fades, but
295 may make the fades take longer than the specified \fIfadeSeconds\fP if
296 your server isn't fast enough to keep up. Default 20.
298 .B captureStderr\fP (class \fBBoolean\fP)
299 Whether \fIxscreensaver\fP should redirect its stdout and stderr streams to
300 the window itself. Since its nature is to take over the screen, you would not
301 normally see error messages generated by xscreensaver or the sub-programs it
302 runs; this resource will cause the output of all relevant programs to be
303 drawn on the screensaver window itself, as well as being written to the
304 controlling terminal of the screensaver driver process. Default true.
306 .B font\fP (class \fBFont\fP)
307 The font used for the stdout/stderr text, if \fBcaptureStderr\fP is true.
308 Default \fB*\-medium\-r\-*\-140\-*\-m\-*\fP (a 14 point fixed-width font.)
310 .B mode\fP (class \fBMode\fP)
311 Controls the behavior of xscreensaver. Legal values are:
315 When blanking the screen, select a random display mode from among those
316 that are enabled and applicable. This is the default.
319 When blanking the screen, only ever use one particular display mode (the
320 one indicated by the \fIselected\fP setting.)
323 When blanking the screen, just go black: don't run any graphics hacks.
326 Don't ever blank the screen, and don't ever allow the monitor to power down.
330 .B selected\fP (class \fBInteger\fP)
331 When \fImode\fP is set to \fIone\fP, this is the one, indicated by its
332 index in the \fIprograms\fP list. You're crazy if you count them and
333 set this number by hand: let
334 .BR xscreensaver\-demo (1)
337 .B programs\fP (class \fBPrograms\fP)
338 The graphics hacks which \fIxscreensaver\fP runs when the user is idle.
339 The value of this resource is a string, one \fIsh\fP-syntax command per line.
340 Each line must contain exactly one command: no semicolons, no ampersands.
342 When the screensaver starts up, one of these is selected at random, and
343 run. After the \fIcycle\fP period expires, it is killed, and another
346 If a line begins with a dash (-) then that particular program is
347 disabled: it won't be selected at random (though you can still select
348 it explicitly using the
349 .BR xscreensaver\-demo (1)
352 If all programs are disabled, then the screen will just be made blank,
353 as when \fImode\fP is set to \fIblank\fP.
355 To disable a program, you must mark it as disabled with a dash instead
356 of removing it from the list. This is because the system-wide (app-defaults)
357 and per-user (.xscreensaver) settings are merged together, and if a user
358 just \fIdeletes\fP an entry from their programs list, but that entry still
359 exists in the system-wide list, then it will come back. However, if the
360 user \fIdisables\fP it, then their setting takes precedence.
362 If the display has multiple screens, then a different program will be run
363 for each screen. (All screens are blanked and unblanked simultaniously.)
365 Note that you must escape the newlines; here is an example of how you
366 might set this in your \fI~/.xscreensaver\fP file:
372 ico -r -faces -sleep 1 -obj ico \\n\\
373 xdaliclock -builtin2 -root \\n\\
374 xv -root -rmode 5 image.gif -quit \\n
378 Make sure your \fB$PATH\fP environment variable is set up correctly
379 \fIbefore\fP xscreensaver is launched, or it won't be able to find the
380 programs listed in the \fIprograms\fP resource.
382 To use a program as a screensaver, two things are required: that that
383 program draw on the root window (or be able to be configured to draw on
384 the root window); and that that program understand ``virtual root''
385 windows, as used by virtual window managers such as
387 (Generally, this is accomplished by just including the \fI"vroot.h"\fP
388 header file in the program's source.)
390 If there are some programs that you want to run only when using a color
391 display, and others that you want to run only when using a monochrome
392 display, you can specify that like this:
394 mono: mono-program -root \\n\\
395 color: color-program -root \\n\\
399 More generally, you can specify the kind of visual that should be used for
400 the window on which the program will be drawing. For example, if one
401 program works best if it has a colormap, but another works best if it has
402 a 24-bit visual, both can be accommodated:
404 PseudoColor: cmap-program -root \\n\\
405 TrueColor: 24bit-program -root \\n\\
409 In addition to the symbolic visual names described above (in the discussion
410 of the \fIvisualID\fP resource) one other visual name is supported in
411 the \fIprograms\fP list:
415 This is like \fBdefault\fP, but also requests the use of the default colormap,
416 instead of a private colormap. (That is, it behaves as if
417 the \fI\-no\-install\fP command-line option was specified, but only for
418 this particular hack.) This is provided because some third-party programs
419 that draw on the root window (notably:
423 make assumptions about the visual and colormap of the root window:
424 assumptions which xscreensaver can violate.
427 If you specify a particular visual for a program, and that visual does not
428 exist on the screen, then that program will not be chosen to run. This
429 means that on displays with multiple screens of different depths, you can
430 arrange for appropriate hacks to be run on each. For example, if one screen
431 is color and the other is monochrome, hacks that look good in mono can be
432 run on one, and hacks that only look good in color will show up on the other.
436 Normally you won't need to change the following resources:
439 .B pointerPollTime\fP (class \fBTime\fP)
440 When server extensions are not in use, this controls how
441 frequently \fIxscreensaver\fP checks to see if the mouse position or buttons
442 have changed. Default 5 seconds.
444 .B windowCreationTimeout\fP (class \fBTime\fP)
445 When server extensions are not in use, this controls the delay between when
446 windows are created and when \fIxscreensaver\fP selects events on them.
449 .B initialDelay\fP (class \fBTime\fP)
450 When server extensions are not in use, \fIxscreensaver\fP will wait this many
451 seconds before selecting events on existing windows, under the assumption that
452 \fIxscreensaver\fP is started during your login procedure, and the window
453 state may be in flux. Default 0. (This used to default to 30, but that was
454 back in the days when slow machines and X terminals were more common...)
456 .B sgiSaverExtension\fP (class \fBBoolean\fP)
457 There are a number of different X server extensions which can make
458 xscreensaver's job easier. The next few resources specify whether these
459 extensions should be utilized if they are available.
461 This resource controls whether the SGI \fBSCREEN_SAVER\fP server extension
462 will be used to decide whether the user is idle. This is the default
463 if \fIxscreensaver\fP has been compiled with support for this
464 extension (which is the default on SGI systems.). If it is available,
465 the \fBSCREEN_SAVER\fP method is faster and more reliable than what will
466 be done otherwise, so use it if you can. (This extension is only available
467 on Silicon Graphics systems, unfortunately.)
469 .B mitSaverExtension\fP (class \fBBoolean\fP)
470 This resource controls whether the \fBMIT\-SCREEN\-SAVER\fP server extension
471 will be used to decide whether the user is idle. However, the default for
472 this resource is \fIfalse\fP, because even if this extension is available,
473 it is flaky (and it also makes the \fBfade\fP option not work properly.)
474 Use of this extension is not recommended.
476 .B xidleExtension\fP (class \fBBoolean\fP)
477 This resource controls whether the \fBXIDLE\fP server extension will be
478 used to decide whether the user is idle. This is the default
479 if \fIxscreensaver\fP has been compiled with support for this extension.
480 (This extension is only available for X11R4 and X11R5 systems, unfortunately.)
482 .B procInterrupts\fP (class \fBBoolean\fP)
483 This resource controls whether the \fB/proc/interrupts\fP file should be
484 consulted to decide whether the user is idle. This is the default
485 if \fIxscreensaver\fP has been compiled on a system which supports this
486 mechanism (i.e., Linux systems.)
488 The benefit to doing this is that \fIxscreensaver\fP can note that the user
489 is active even when the X console is not the active one: if the user is
490 typing in another virtual console, xscreensaver will notice that and will
491 fail to activate. For example, if you're playing Quake in VGA-mode,
492 xscreensaver won't wake up in the middle of your game and start competing
495 The drawback to doing this is that perhaps you \fIreally do\fP want idleness
496 on the X console to cause the X display to lock, even if there is activity
497 on other virtual consoles. If you want that, then set this option to False.
498 (Or just lock the X console manually.)
500 The default value for this resource is True, on systems where it works.
502 .B overlayStderr\fP (class \fBBoolean\fP)
503 If \fBcaptureStderr\fP is True, and your server supports ``overlay'' visuals,
504 then the text will be written into one of the higher layers instead of into
505 the same layer as the running screenhack. Set this to False to disable
506 that (though you shouldn't need to.)
508 .B overlayTextForeground\fP (class \fBForeground\fP)
509 The foreground color used for the stdout/stderr text, if \fBcaptureStderr\fP
510 is true. Default: Yellow.
512 .B overlayTextBackground\fP (class \fBBackground\fP)
513 The background color used for the stdout/stderr text, if \fBcaptureStderr\fP
514 is true. Default: Black.
516 .B bourneShell\fP (class \fBBourneShell\fP)
517 The pathname of the shell that \fIxscreensaver\fP uses to start subprocesses.
518 This must be whatever your local variant of \fB/bin/sh\fP is: in particular,
519 it must not be \fBcsh\fP.
520 .SH COMMAND-LINE OPTIONS
522 also accepts a few command-line options, mostly for use when debugging:
523 for normal operation, you should configure things via the \fI~/.xscreensaver\fP
526 .B \-display \fIhost:display.screen\fP
527 The X display to use. For displays with multiple screens, XScreenSaver
528 will manage all screens on the display simultaniously.
531 Same as setting the \fIverbose\fP resource to \fItrue\fP: print diagnostics
532 on stderr and on the xscreensaver window.
534 .B \-no-capture-stderr
535 Same as setting the \fIcaptureStderr\fP resource to \fIfalse\fP: do not
536 redirect the stdout and stderr streams to the xscreensaver window itself.
537 If xscreensaver is crashing, you might need to do this in order to see
540 When it is time to activate the screensaver, a full-screen black window is
541 created on each screen of the display. Each window is created in such a way
542 that, to any subsequently-created programs, it will appear to be a ``virtual
543 root'' window. Because of this, any program which draws on the root
544 window (and which understands virtual roots) can be used as a screensaver.
546 When the user becomes active again, the screensaver windows are unmapped, and
547 the running subprocesses are killed by sending them \fBSIGTERM\fP. This is
548 also how the subprocesses are killed when the screensaver decides that it's
549 time to run a different demo: the old one is killed and a new one is launched.
551 Before launching a subprocess, \fIxscreensaver\fP stores an appropriate value
552 for \fB$DISPLAY\fP in the environment that the child will receive. (This is
553 so that if you start \fIxscreensaver\fP with a \fI-display\fP argument, the
554 programs which \fIxscreensaver\fP launches will draw on the same display;
555 and so that the child will end up drawing on the appropriate screen of a
556 multi-headed display.)
558 When the screensaver turns off, or is killed, care is taken to restore
559 the ``real'' virtual root window if there is one. Because of this, it is
560 important that you not kill the screensaver process with \fIkill -9\fP if
561 you are running a virtual-root window manager. If you kill it with \-9,
562 you may need to restart your window manager to repair the damage. This
563 isn't an issue if you aren't running a virtual-root window manager.
565 For all the gory details, see the commentary at the top of xscreensaver.c.
567 You can control a running screensaver process by using the
568 .BR xscreensaver\-command (1)
571 Modern X servers contain support to power down the monitor after an idle
572 period. If the monitor has powered down, then \fIxscreensaver\fP will
573 notice this (after a few minutes), and will not waste CPU by drawing
574 graphics demos on a black screen. An attempt will also be made to
575 explicitly power the monitor back up as soon as user activity is detected.
577 As of version 3.28, the \fI~/.xscreensaver\fP file controls the
578 configuration of your display's power management settings: if you have
581 to change your power management settings, then xscreensaver will
582 override those changes with the values specified
583 in \fI~/.xscreensaver\fP (or with its built-in defaults, if there
584 is no \fI~/.xscreensaver\fP file yet.)
586 To change your power management settings, run
587 .BR xscreensaver\-demo (1)
588 and change the various timeouts through the user interface.
589 Alternately, you can edit the \fI~/.xscreensaver\fP file directly.
591 If the power management section is grayed out in the
592 .BR xscreensaver\-demo (1)
593 window, then that means that your X server does not support
594 the XDPMS extension, and so control over the monitor's power state
597 If you're using a laptop, don't be surprised if changing the DPMS
598 settings has no effect: many laptops have monitor power-saving behavior
599 built in at a very low level that is invisible to Unix and X. On such
600 systems, you can typically adjust the power-saving delays only by
601 changing settings in the BIOS in some hardware-specific way.
603 You can run \fIxscreensaver\fP from your
605 session, so that the screensaver will run even when nobody is logged
608 The trick to using xscreensaver with \fIxdm\fP is this: keep in mind the
609 two very different states in which xscreensaver will be running:
612 .B 1: Nobody logged in.
614 If you're thinking of running xscreensaver from XDM at all, then it's
615 probably because you want graphics demos to be running on the console
616 when nobody is logged in there. In this case, xscreensaver will function
617 only as a screen saver, not a screen locker: it doesn't make sense
618 for xscreensaver to lock the screen, since nobody is logged in yet!
619 The only thing on the screen is the XDM login prompt.
621 .B 2: Somebody logged in.
623 Once someone has logged in through the XDM login window, the situation is
624 very different. For example: now it makes sense to lock the screen (and
625 prompt for the logged in user's password); and now xscreensaver should
626 consult that user's \fI~/.xscreensaver\fP file; and so on.
629 The difference between these two states comes down to a question of,
630 which user is the \fIxscreensaver\fP process running as? For the first
631 state, it doesn't matter. If you start \fIxscreensaver\fP in the usual
632 XDM way, then xscreensaver will probably end up running as root, which
633 is fine for the first case (the ``nobody logged in'' case.)
635 However, once someone is logged in, running as root is no longer fine:
636 because xscreensaver will be consulting root's \fI.xscreensaver\fP file
637 instead of that of the logged in user, and won't be prompting for the
638 logged in user's password, and so on. (This is not a security problem,
639 it's just not what you want.)
641 So, once someone has logged in, you want xscreensaver to be running as that
642 user. The way to accomplish this is to kill the old xscreensaver process
643 and start a new one (as the new user.)
645 The simplest way to accomplish all of this is as follows:
648 .B 1: Launch xscreensaver before anyone logs in.
650 To the file \fI/usr/lib/X11/xdm/Xsetup\fP, add the lines
653 xscreensaver-command -exit
656 This will run xscreensaver as root, over the XDM login window.
657 Moving the mouse will cause the screen to un-blank, and allow the user
658 to type their password at XDM to log in.
660 .B 2: Restart xscreensaver when someone logs in.
662 Near the top of the file \fI/usr/lib/X11/xdm/Xsession\fP, add those same lines:
664 xscreensaver-command -exit
667 When someone logs in, this will kill off the existing (root) xscreensaver
668 process, and start a new one, running as the user who has just logged in.
669 If the user's .xscreensaver file requests locking, they'll get it. They
670 will also get their own choice of timeouts, and graphics demos, and so on.
672 Alternately, each user could just put those lines in their
673 personal \fI~/.xsession\fP files.
676 Make sure you have \fB$PATH\fP set up correctly in the \fIXsetup\fP
677 and \fIXsession\fP scripts, or \fIxdm\fP won't be able to
678 find \fIxscreensaver\fP, and/or \fIxscreensaver\fP won't be able to
679 find its graphics demos.
681 (If your system does not seem to be executing the \fIXsetup\fP file, you
682 may need to configure it to do so: the traditional way to do this is
683 to make that file the value of the \fIDisplayManager*setup\fP resource
684 in the \fI/usr/lib/X11/xdm/xdm-config\fP file. See the man page for
688 It is safe to run \fIxscreensaver\fP as root (as \fIxdm\fP is likely to do.)
689 If run as root, \fIxscreensaver\fP changes its effective user and group ids
690 to something safe (like \fI"nobody"\fP) before connecting to the X server
691 or launching user-specified programs.
693 An unfortunate side effect of this (important) security precaution is that
694 it may conflict with cookie-based authentication.
696 If you get "connection refused" errors when running \fIxscreensaver\fP
697 from \fIxdm\fP, then this probably means that you have
699 or some other security mechanism turned on. One way around this is to
700 add \fB"xhost\ +localhost"\fP to \fIXsetup\fP, just before \fIxscreensaver\fP
703 Note that this will give access to the X server to anyone capable of logging
704 in to the local machine, so in some environments, this might not be
705 appropriate. If turning off file-system-based access control is not
706 acceptable, then running \fIxscreensaver\fP from the \fIXsetup\fP file
707 might not be possible, and xscreensaver will only work when running as
708 a normal, unprivileged user.
710 For more information on the X server's access control mechanisms, see the
718 The instructions for using \fIxscreensaver\fP with
720 are almost the same as for using
722 above. There are only two differences, really: instead
723 of editing \fI/usr/lib/X11/xdm/Xsetup\fP, edit the
724 file \fI/etc/X11/gdm/Init/Default\fP; and instead of
725 editing \fI/usr/lib/X11/xdm/Xsession\fP, edit one or all of the
726 files in the \fI/etc/X11/gdm/Sessions/\fP directory. (Note that
727 the default session (\fI/etc/X11/gdm/Sessions/Default\fP) usually
728 simply executes \fI/usr/lib/X11/xdm/Xsession\fP, so be careful
729 you aren't initializing xscreensaver twice.)
731 All the same caveats apply for
735 .SH USING CDE (COMMON DESKTOP ENVIRONMENT)
736 The easiest way to use \fIxscreensaver\fP on a system with CDE is to simply
737 switch off the built-in CDE screensaver, and use \fIxscreensaver\fP instead;
738 and second, to tell the front panel to run
739 .BR xscreensaver\-command (1)
740 with the \fI\-lock\fP option when the \fILock\fP icon is clicked.
742 To accomplish this involves five steps:
745 \fB1: Switch off CDE's locker\fP
746 Do this by turning off ``\fIScreen Saver and Screen Lock\fP'' in the
747 Screen section of the Style Manager.
749 \fB2: Edit sessionetc\fP
750 Edit the file \fI~/.dt/sessions/sessionetc\fP and add to it the line
754 And make sure the sessionetc file is executable.
755 This will cause \fIxscreensaver\fP to be launched when you log in.
756 (As always, make sure that xscreensaver and the graphics demos are on
757 your \fB$PATH\fP; the path needs to be set in \fI.cshrc\fP
758 and/or \fI.dtprofile\fP, not \fI.login\fP.)
760 \fB3: Create XScreenSaver.dt\fP
761 Create a file called \fI~/.dt/types/XScreenSaver.dt\fP with the following
768 EXEC_STRING xscreensaver-command -lock
773 This defines a ``lock'' command for the CDE front panel, that knows how
774 to talk to \fIxscreensaver\fP.
776 \fB4: Create Lock.fp\fP
777 Create a file called \fI~/.dt/types/Lock.fp\fP with the following
783 CONTAINER_NAME Switch
784 CONTAINER_TYPE SWITCH
788 PUSH_ACTION XScreenSaver
789 HELP_TOPIC FPOnItemLock
793 This associates the CDE front panel ``Lock'' icon with the lock command
794 we just defined in step 3.
797 Select ``\fIRestart Workspace Manager\fP'' from the popup menu to make
798 your changes take effect. If things seem not to be working, check the
799 file \fI~/.dt/errorlog\fP for error messages.
801 .SH USING HP VUE (VISUAL USER ENVIRONMENT)
802 Since CDE is a descendant of VUE, the instructions for using xscreensaver
803 under VUE are similar to the above:
806 \fB1: Switch off VUE's locker\fP
807 Open the ``\fIStyle Manager\fP'' and select ``\fIScreen\fP.''
808 Turn off ``\fIScreen Saver and Screen Lock\fP'' option.
810 \fB2: Make sure you have a Session\fP
811 Next, go to the Style Manager's, ``\fIStartup\fP'' page.
812 Click on ``\fISet Home Session\fP'' to create a session, then
813 on ``\fIReturn to Home Session\fP'' to select this session each
816 \fB3: Edit vue.session\fP
817 Edit the file \fI~/.vue/sessions/home/vue.session\fP and add to it
820 vuesmcmd -screen 0 -cmd "xscreensaver"
822 This will cause \fIxscreensaver\fP to be launched when you log in.
823 (As always, make sure that xscreensaver and the graphics demos are on
824 your \fB$PATH\fP; the path needs to be set in \fI.cshrc\fP
825 and/or \fI.profile\fP, not \fI.login\fP.)
827 \fB3: Edit vuewmrc\fP
828 Edit the file \fI~/.vue/vuewmrc\fP and add (or change) the Lock control:
834 PUSH_ACTION f.exec "xscreensaver-command -lock"
838 This associates the VUE front panel ``Lock'' icon with the xscreensaver
844 .BR xscreensaver-command (1)
845 program is a perfect candidate for something to add to your window manager's
846 popup menus. If you use
850 or (probably) any of \fItwm\fP's many descendants, you can do it like this:
853 \fB1. Create ~/.mwmrc (or ~/.twmrc or ...)\fP
854 If you don't have a \fI~/.mwmrc\fP file (or, on SGIs, a \fI~/.4Dwmrc\fP file;
855 or, with twm, a \fI~/.twmrc\fP file) then create one by making a copy of
856 the \fI/usr/lib/X11/system.mwmrc\fP
857 file (or \fI/usr/lib/X11/twm/system.twmrc\fP, and so on.)
859 \fB2. Add a menu definition.\fP
864 "Blank Screen Now" !"sleep 3; xscreensaver-command -activate"
865 "Lock Screen Now" !"sleep 3; xscreensaver-command -lock"
866 "Screen Saver Demo" !"xscreensaver-demo"
867 "Screen Saver Preferences" !"xscreensaver-demo -prefs"
868 "Reinitialize Screen Saver" !"xscreensaver-command -restart"
869 "Kill Screen Saver" !"xscreensaver-command -exit"
870 "Launch Screen Saver" !"xscreensaver &"
874 \fB3. Add the menu\fP
879 find the section of the file that says \fIMenu DefaultRootMenu\fP.
882 it will probably be \fImenu "defops"\fP. If you add a line somewhere
883 in that menu definition that reads
885 "XScreenSaver" f.menu XScreenSaver
887 then this will add an XScreenSaver sub-menu to your default root-window
888 popup menu. Alternately, you could just put the xscreensaver menu items
889 directly into the root menu.
892 For Fvwm2, the process is similar: first create a \fI~/.fvwm2rc\fP file
893 if you don't already have one, by making a copy of
894 the \fI/etc/X11/fvwm2/system.fvwm2rc\fP file. Then, add a menu definition
897 AddToMenu XScreenSaver "XScreenSaver" Title
898 + "Blank Screen Now" Exec xscreensaver-command -activate
899 + "Lock Screen Now" Exec xscreensaver-command -lock
900 + "Screen Saver Demo" Exec xscreensaver-command -demo
901 + "Screen Saver Preferences" Exec xscreensaver-command -prefs
902 + "Reinitialize Screen Saver" Exec xscreensaver-command -restart
903 + "Kill Screen Saver" Exec xscreensaver-command -exit
904 + "Launch Screen Saver" Exec xscreensaver
905 + "Run Next Demo" Exec xscreensaver-command -next
906 + "Run Previous Demo" Exec xscreensaver-command -prev
908 # To put the XScreenSaver sub-menu at the end of the root menu:
909 AddToMenu RootMenu "XScreenSaver" Popup XScreenSaver
911 The Enlightenment window manager keeps each of its menus in a separate
912 file. So, you need to create a file
913 named \fI~/.enlightenment/xscreensaver.menu\fP with the contents:
915 "XScreenSaver Commands"
916 "Blank Screen Now" NULL exec "xscreensaver-command -activate"
917 "Lock Screen Now" NULL exec "xscreensaver-command -lock"
918 "Screen Saver Demo" NULL exec "xscreensaver-command -demo"
919 "Screen Saver Prefs" NULL exec "xscreensaver-command -prefs"
920 "Reinitialize Saver" NULL exec "xscreensaver-command -restart"
921 "Kill Screen Saver" NULL exec "xscreensaver-command -exit"
922 "Launch Screen Saver" NULL exec "xscreensaver"
926 "XScreenSaver" NULL menu "xscreensaver.menu"
928 to \fI~/.enlightenment/file.menu\fP to put the XScreenSaver submenu on
929 your left-button root-window menu.
931 As you see, every window manager does this stuff gratuitously differently,
932 just to make your life difficult. You are in a maze of twisty menu
933 configuration languages, all alike.
935 Bugs? There are no bugs. Ok, well, maybe. If you find one, please let
936 me know. http://www.jwz.org/xscreensaver/bugs.html explains how to
937 construct the most useful bug reports.
940 If xscreensaver has been launched from
942 before anyone has logged in, you will need to kill and then restart the
943 xscreensaver daemon after you have logged in, or you will be confused by
944 the results. (For example, locking won't work, and your \fI~/.xscreensaver\fP
945 file will be ignored.)
947 When you are logged in, you want the \fIxscreensaver\fP daemon to be
948 running under \fIyour\fP user id, not as root or some other user.
950 If it has already been started by \fIxdm\fP, you can kill it by sending
951 it the \fBexit\fP command, and then re-launching it as you, by putting
952 something like the following in your personal X startup script:
954 xscreensaver-command -exit
957 The ``\fIUsing XDM(1)\fP'' section, above, goes into more detail, and explains
958 how to configure the system to do this for all users automatically.
960 .B Locking and root logins
961 In order for it to be safe for xscreensaver to be launched by \fIxdm\fP,
962 certain precautions had to be taken, among them that xscreensaver never
963 runs as \fIroot\fP. In particular, if it is launched as root (as \fIxdm\fP
964 is likely to do), xscreensaver will disavow its privileges, and switch
965 itself to a safe user id (such as \fInobody\fP.)
967 An implication of this is that if you log in as \fIroot\fP on the console,
968 xscreensaver will refuse to lock the screen (because it can't tell
969 the difference between \fIroot\fP being logged in on the console, and a
970 normal user being logged in on the console but xscreensaver having been
976 The solution to this is simple: you shouldn't be logging in on the console
977 as \fIroot\fP in the first place! (What, are you crazy or something?)
979 Proper Unix hygiene dictates that you should log in as yourself, and
981 to \fIroot\fP as necessary. People who spend their day logged in
982 as \fIroot\fP are just begging for disaster.
985 For xscreensaver to work when launched by
987 programs running on the local machine as user \fI"nobody"\fP must be
988 able to connect to the X server. This means that if you want to run
989 xscreensaver on the console while nobody is logged in, you may need
990 to disable cookie-based access control (and allow all users who can log
991 in to the local machine to connect to the display.)
993 You should be sure that this is an acceptable thing to do in your
994 environment before doing it. See the ``\fIUsing XDM(1)\fP'' section,
995 above, for more details.
997 If anyone has suggestions on how xscreensaver could be made to work with
999 without first turning off \fI.Xauthority\fP-based access control, please
1003 If you get an error message at startup like ``couldn't get password
1004 of \fIuser\fP'' then this probably means that you're on a system in which
1007 library routine can only be effectively used by root. If this is the case,
1008 then \fIxscreensaver\fP must be installed as setuid to root in order for
1009 locking to work. Care has been taken to make this a safe thing to do.
1011 It also may mean that your system uses shadow passwords instead of the standard
1013 interface; in that case, you may need to change some options
1014 with \fIconfigure\fP and recompile.
1016 If you change your password after xscreensaver has been launched, it will
1017 continue using your old password to unlock the screen until xscreensaver
1018 is restarted. So, after you change your password, you'll have to do
1020 xscreensaver-command -restart
1022 to make \fIxscreensaver\fP notice.
1025 If your system uses PAM (Pluggable Authentication Modules), then in order
1026 for xscreensaver to use PAM properly, PAM must be told about xscreensaver.
1027 The xscreensaver installation process should update the PAM data (on Linux,
1028 by creating the file \fI/etc/pam.d/xscreensaver\fP for you, and on Solaris,
1029 by telling you what lines to add to the \fI/etc/pam.conf\fP file.)
1031 If the PAM configuration files do not know about xscreensaver, then
1032 you \fImight\fP be in a situation where xscreensaver will refuse to ever
1035 This is a design flaw in PAM (there is no way for a client to tell the
1036 difference between PAM responding ``I have never heard of your module,''
1037 and responding, ``you typed the wrong password.'') As far as I can tell,
1038 there is no way for xscreensaver to automatically work around this, or
1039 detect the problem in advance, so if you have PAM, make sure it is
1040 configured correctly!
1042 .B Colormap lossage: TWM
1043 The \fBinstallColormap\fP option doesn't work very well with the
1045 window manager and its descendants.
1047 There is a race condition between the screensaver and this window manager,
1048 which can result in the screensaver's colormap not getting installed
1049 properly, meaning the graphics hacks will appear in essentially random
1050 colors. (If the screen goes white instead of black, this is probably why.)
1056 window managers don't have this problem. The race condition exists
1057 because X (really, ICCCM) does not provide a way for an OverrideRedirect
1058 window to have its own colormap, short of grabbing the server (which is
1059 neither a good idea, nor really possible with the current design.) What
1060 happens is that, as soon as xscreensaver installs its colormap, \fBtwm\fP
1061 responds to the resultant \fBColormapNotify\fP event by re-instaling the
1062 default colormap. Apparently, \fBtwm\fP doesn't \fIalways\fP do this; it
1063 seems to do it regularly if the screensaver is activated from a menu item,
1064 but seems to not do it if the screensaver comes on of its own volition, or
1065 is activated from another console.
1068 .B Attention, window manager authors!
1069 You should only call
1070 .BR XInstallColormap (3)
1071 in response to user events. That is, it is appropriate to install a colormap
1072 in response to \fBFocusIn\fP, \fBFocusOut\fP, \fBEnterNotify\fP,
1073 and \fBLeaveNotify\fP events; but it is not appropriate to call it in
1074 response to \fBColormapNotify\fP events. If you install colormaps in
1075 response to \fIapplication\fP actions as well as in response to \fIuser\fP
1076 actions, then you create the situation where it is impossible for
1077 override-redirect applications (such as xscreensaver) to display their
1078 windows in the proper colors.
1081 .B Colormap lossage: XV, XAnim, XEarth
1082 Some programs don't operate properly on visuals other than the default one,
1083 or with colormaps other than the default one. See the discussion of the
1084 magic "default-n" visual name in the description of the \fBprograms\fP
1085 resource in the \fIConfiguration\fP section. When programs only work with
1086 the default colormap, you need to use a syntax like this:
1088 default-n: xv -root image-1.gif -quit \\n\\
1089 default-n: xearth -nostars -wait 0 \\n\\
1091 It would also work to turn off the \fBinstallColormap\fP option altogether,
1092 but that would deny extra colors to those programs that \fIcan\fP take
1096 Although this program ``nices'' the subprocesses that it starts,
1097 graphics-intensive subprograms can still overload the machine by causing
1098 the X server process itself (which is not ``niced'') to suck a lot of
1099 cycles. Care should be taken to slow down programs intended for use as
1100 screensavers by inserting strategic calls to
1104 (or making liberal use of any \fI\-delay\fP options which the programs
1107 Note that the OpenGL-based graphics demos are real pigs on machines that
1108 don't have texture hardware.
1110 Also, an active screensaver will cause your X server to be pretty much
1111 permanently swapped in; but the same is true of any program that draws
1117 .B Latency and Responsiveness
1118 If the subprocess is drawing too quickly and the connection to the X
1119 server is a slow one (such as an X terminal running over a phone line) then
1120 the screensaver might not turn off right away when the user becomes active
1123 demo has this problem if being run in full-speed mode). This can be
1124 alleviated by inserting strategic calls to
1126 in code intended for use as a screensaver. This prevents too much graphics
1127 activity from being buffered up.
1129 .B XFree86's Magic Keystrokes
1130 The XFree86 X server traps certain magic keystrokes before client programs ever
1131 see them. Two that are of note are Ctrl+Alt+Backspace, which causes
1132 the X server to exit; and Ctrl+Alt+F\fIn\fP, which switches virtual consoles.
1133 The X server will respond to these keystrokes even if xscreensaver has the
1134 screen locked. Depending on your setup, you might consider this a problem.
1136 Unfortunately, there is no way for xscreensaver itself to override the
1137 interpretation of these keys. If you want to disable Ctrl+Alt+Backspace
1138 globally, you need to set the \fIDontZap\fP flag in
1139 your \fI/etc/X11/XF86Config\fP file. See the
1143 There is no way (as far as I can tell) to disable the VT-switching keystrokes.
1145 Some Linux systems come with a VT_LOCKSWITCH ioctl, that one could
1146 theoretically use to prevent VT-switching while the screen is locked;
1147 but unfortunately, this ioctl can only be used by root, which means
1148 that xscreensaver can't use it (since xscreensaver disavows its privileges
1149 shortly after startup, for security reasons.)
1151 Any suggestions for other solutions to this problem are welcome.
1154 Apparently there are some problems with XView programs getting confused
1155 and thinking that the screensaver window is the real root window even when
1156 the screensaver is not active: ClientMessages intended for the window manager
1157 are sent to the screensaver window instead. This could be solved by making
1158 xscreensaver forward all unrecognised ClientMessages to the real root window,
1159 but there may be other problems as well. If anyone has any insight on the
1160 cause of this problem, please let me know. (XView is an X11 toolkit that
1161 implements the (quite abominable) Sun OpenLook look-and-feel.)
1163 .B MIT Extension and Fading
1164 The \fBMIT-SCREEN-SAVER\fP extension is junk. Don't use it.
1166 When using the \fBMIT-SCREEN-SAVER\fP extension in conjunction with
1167 the \fBfade\fP option, you'll notice an unattractive flicker just before
1168 the fade begins. This is because the server maps a black window just before
1169 it tells the \fIxscreensaver\fP process to activate. The \fIxscreensaver\fP
1170 process immediately unmaps that window, but this results in a flicker. I
1171 haven't figured a way to get around this; it seems to be a fundamental
1172 property of the (mis-) design of this server extension.
1174 It sure would be nice if someone would implement the \fBSGI SCREEN_SAVER\fP
1175 extension in XFree86; it's dead simple, and works far better than the
1176 overengineered and broken \fBMIT-SCREEN-SAVER\fP extension.
1179 If you're running Irix 6.3, you might find that your monitor is powering down
1180 after an hour or two even if you've told it not to. This is fixed by SGI
1181 patches 2447 and 2537.
1183 If you're running Irix 6.5, this bug is back. I don't know a fix.
1185 .B MesaGL and Voodoo Cards
1186 If you have a 3Dfx/Voodoo card, the default settings for xscreensaver will
1187 run the GL-based graphics demos in such a way that they will not take
1188 advantage of the 3D acceleration hardware. The solution is to change
1189 the \fBprograms\fP entries for the GL hacks from this:
1195 MESA_GLX_FX=fullscreen gears \\n\\
1197 That is, make sure that \fB$MESA_GLX_FX\fP is set to \fIfullscreen\fP, and
1198 don't tell the program to draw on the root window. This may seem strange,
1199 but the setup used by Mesa and these kinds of cards \fIis\fP strange!
1201 For those who don't know, these cards work by sitting between your normal
1202 video card and the monitor, and seizing control of the monitor when it's
1203 time to do 3D. But this means that accelerated 3D only happens in full-screen
1204 mode (you can't do it in a window, and you can't see the output of 3D and 2D
1205 programs simultaniously), and that 3D will probably drive your monitor at a
1206 lower resolution, as well. It's bizarre.
1208 This probably isn't ever necessary on more modern cards; I'm not sure.
1210 If you find that GL programs only work properly when run as root, and not
1211 as normal users, then the problem is that your \fI/dev/3dfx\fP file is not
1212 configured properly. Check the Linux 3Dfx FAQ.
1215 If \fIprocInterrupts\fP is on (which is the default on Linux systems) and
1216 you're using some program that toggles the state of your keyboard LEDs,
1217 xscreensaver won't work right: turning those LEDs on or off causes a
1218 keyboard interrupt, which xscreensaver will interpret as user activity.
1219 So if you're using such a program, set the \fIprocInterrupts\fP resource
1223 If you are not making use of one of the server extensions (\fBXIDLE\fP,
1224 \fBSGI SCREEN_SAVER\fP, or \fBMIT-SCREEN-SAVER\fP), then it is possible, in
1225 rare situations, for \fIxscreensaver\fP to interfere with event propagation
1226 and make another X program malfunction. For this to occur, that other
1227 application would need to \fInot\fP select \fBKeyPress\fP events on its
1228 non-leaf windows within the first 30 seconds of their existence, but then
1229 select for them later. In this case, that client \fImight\fP fail to receive
1230 those events. This isn't very likely, since programs generally select a
1231 constant set of events immediately after creating their windows and then
1232 don't change them, but this is the reason that it's a good idea to install
1233 and use one of the server extensions instead, to work around this shortcoming
1236 In all these years, I've not heard of even a single case of this happening,
1237 but it is theoretically possible, so I'm mentioning it for completeness...
1240 There need to be a lot more graphics hacks. In particular, there should be
1241 a simulation of a Lavalite (tm).
1246 to get the default host and display number, and to inform the sub-programs
1247 of the screen on which to draw.
1250 to find the sub-programs to run.
1253 for the directory in which to read the \fI.xscreensaver\fP file.
1256 to get the name of a resource file that overrides the global resources
1257 stored in the RESOURCE_MANAGER property.
1259 The latest version of xscreensaver, an online version of this manual,
1260 and a FAQ can always be found at http://www.jwz.org/xscreensaver/
1263 .BR xscreensaver\-demo (1),
1264 .BR xscreensaver\-command (1),
1265 .BR xscreensaver\-gl\-helper (1),
1286 .BR decayscreen (1),
1311 .BR interference (1),
1314 .BR kaleidescope (1),
1346 .BR slidescreen (1),
1357 .BR superquadrics (1),
1372 .BR xbouncebits (1),
1384 Copyright \(co 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
1385 2000, 2001, 2002 by Jamie Zawinski. Permission to use, copy, modify,
1386 distribute, and sell this software and its documentation for any
1387 purpose is hereby granted without fee, provided that the above
1388 copyright notice appear in all copies and that both that copyright
1389 notice and this permission notice appear in supporting documentation.
1390 No representations are made about the suitability of this software for
1391 any purpose. It is provided "as is" without express or implied
1394 Jamie Zawinski <jwz@jwz.org>. Written in late 1991; version 1.0 posted
1395 to comp.sources.x on 17-Aug-1992.
1397 Please let me know if you find any bugs or make any improvements.
1398 .SH ACKNOWLEDGEMENTS
1399 Thanks to Angela Goodman for the XScreenSaver logo.
1401 Thanks to the many people who have contributed graphics demos to the package.
1403 Thanks to David Wojtowicz for implementing \fIlockTimeout\fP.
1405 Thanks to Martin Kraemer for adding support for shadow passwords and
1406 locking-disabled diagnostics.
1408 Thanks to Patrick Moreau for the VMS port.
1410 Thanks to Mark Bowyer for figuring out how to hook it up to CDE.
1412 Thanks to Nat Lanza for the Kerberos support.
1414 Thanks to Bill Nottingham for the initial PAM support.
1416 And thanks to Jon A. Christopher for implementing the Athena dialog
1417 support, back in the days before Lesstif or Gtk were viable alternatives