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Archive-name: motif-faq/part9
Last-modified: 1 FEB 2002
Posting-Frequency: irregular
Organization: Kenton Lee, X/Motif Consultant, http://www.rahul.net/kenton/
URL: http://www.rahul.net/kenton/mfaq.html
Version: 8.1
-----------------------------------------------------------------------------
Subject: 293) Why doesn't the Help callback work on some widgets?
[Last modified: May 95]
Answer: If you press the help key the help callback of the widget with the
keyboard focus is called (not the one containing the mouse). You can't get
the help callback of a non-keyboard-selectable widget called. To get `context
sensitive' help on these, you have to find the mouse, associate its position
with a widget and then do the help.
The X Resource, Issue 6, has an article on implementing context help in Motif
in this manner, that is, using the mouse position to indicate the widget for
which context help is desired, as well as using resources to specify the help.
The demo program lets you toggle between using the method described in the
article and XmTrackingLocate() for comparision purposes.
Contributed by: Jay Schmidgall jay@vnet.ibm.com (author of the article
mentioned above). Thanks to chen@adi.com (Franklin Chen) for correcting the
URL.
-----------------------------------------------------------------------------
Subject: 294)* How can I implement "bubble help" or "tool tips" with Motif?
[Last modified: Jan 02]
Answer: Open Motif 2.2 includes a built-in ToolTips feature. The following
material may be of interest to users of earlier versions of Motif.
Gary Aviv (gary@compgen.com) informed this maintainer about the free LiteClue
widget from Computer Generation, Inc. (http://www.compgen.com/). LiteClue is
a widget which pops a one line help message when the user passes the pointer
over another "watched" widget. This is known by various names in the industry
such as hints, clues, tips, bubble help and balloon help. Technical
documentation and source for the LiteClue widget are available from:
http://www.compgen.com/widgets/LiteClue.html
ftp://ftp.compgen.com/pub/widgets/LiteClue.tar.Z
Ken Lee (http://www.rahul.net/kenton/) writes: A simple technique is to popup
a shell containing your message whenever an enter event occurs (possibly
delayed by a timer) and pop it down again after a leave event.
David Lewis (dbl@ics.com) writes: To those resources I should add that the
XmHTML sources (HTML parser, browser, etc) have this ToolTip/bubble-help/popup
feature, in readily-usable code. In addition, the ICS EnhancementPak widget
set (http://www.ics.com) has both a toolbar with built-in popups for its
entries and a small library which adds popup capabilities to any widget.
-----------------------------------------------------------------------------
Subject: 295) Can I specify a widget in a resource file?
Answer: This answer, which uses the Xmu library, is due to David Elliott. If
the converter is added, then the name of a widget (a string) can be used in
resource files, and will be converted to the appropriate widget.
This code, which was basically stolen from the Athena Form widget, adds a
String to Widget converter. I wrote it as a general routine that I call at
the beginning of all of my programs, and made it so I could add other
converters as needed (like String to Unit Type ;-).
#include <X11/Intrinsic.h>
#include <X11/StringDefs.h>
#include <Xm/Xm.h>
#include <X11/Xmu/Converters.h>
#include <X11/IntrinsicP.h>
#include <X11/CoreP.h>
void
setupConverters()
{
static XtConvertArgRec parentCvtArgs[] = {
{XtBaseOffset, (caddr_t)XtOffset(Widget, core.parent),
sizeof(Widget)}
};
XtAddConverter(XmRString, XmRWindow, XmuCvtStringToWidget,
parentCvtArgs, XtNumber(parentCvtArgs));
}
-----------------------------------------------------------------------------
Subject: 296) Why are only some of my translations are being installed? I
have a translation table like the following, but only the first ones are
getting installed and the rest are ignored.
*Text.translations: #override \
Ctrl<Key>a: beginning-of-line() \n\
Ctrl<Key>e: end-of-line() \n\
Ctrl<Key>f: forward-character() \n\
Answer: Most likely, you have a space at the end of one of the lines (the
first in this case).
Ctrl<Key>a: beginning-of-line() \n\
^ space here
The second backslash in each line is there to protect the real newline
character and so you must not follow it with anything other than the newline
itself. Otherwise it acts as the end of the resource definition and the
remaining lines are not added.
-----------------------------------------------------------------------------
Subject: 297) Can I have separate translations for shifted and unshifted
keys?
[Last modified: Jan 99]
Answer: Alec Flett <alecf@netscape.com> writes:
I've got an addition for the motif FAQ that just solved a problem I've been
wrestling with for a month - it's really an addition to #303 "Why are only
some of my translations being installed?"
On certain platforms you cannot use an upper-case key in combination with the
Shift modifier. For example,
Meta Shift <Key>F: find-in-list()
will not always work because the F is capitalized.
The reason for this is because some platforms (such as IRIX) distinguish upper
case and lowercase keysyms. Using Jamie Zawinski's xkeycaps program
(http://www.jwz.org/xkeycaps/), you will see that on Solaris the "F" key just
has one keysym: "F" On IRIX they same key has two: "f" and "F".
-----------------------------------------------------------------------------
Subject: 298) What are these "non-existant passive grab" warnings? When I
destroy certain widgets I get a stream of messages
Warning: Attempt to remove non-existant passive grab
Answer: They are meaningless, and you want to ignore them. Do this (from Kee
Hinckley) by installing an XtWarning handler that explicitly looks for them
and discards them:
static void xtWarnCB(String message) {
if (asi_strstr(message, "non-existant passive grab", TRUE)) return;
...
They come from Xt, and (W. Scott Meeks): "it's something that the designers of
Xt decided the toolkit should do. Unfortunately, Motif winds up putting
passive grabs all over the place for the menu system. On the one hand, we
want to remove all these grabs when menus get destroyed so that they don't
leak memory; on the other hand, it's almost impossible to keep track of all
the grabs, so we have a conservative strategy of ungrabbing any place where a
grab could have been made and we don't explicitly know that there is no grab.
The unfortunate side effect is the little passive grab warning messages.
We're trying to clean these up where possible, but there are some new places
where the warning is generated. Until we get this completely cleaned up (1.2
maybe), your best bet is probably to use a warning handler."
-----------------------------------------------------------------------------
Subject: 299) How do I have more buttons than three in a MessageBox? I want
to have something like a MessageBox (or other widget) with more than three
buttons, but with the same nice appearance.
[Last modified: Feb 95]
Answer: The Motif 1.2 MessageBox widget allows extra buttons to be added after
the OK button. Just create the extra buttons as children of the MessageBox.
Similarly with the SelectionBox.
Pre-Motif 1.2, you have to do one of the following methods.
A SelectionBox is created with four buttons, but the fourth (the Apply button)
is unmanaged. To manage it get its widget ID via
XmSelectionBoxGetChild(parent, XmDIALOG_APPLY_BUTTON) and then XtManage it.
Unmanage all of the other bits in the SelectionBox that you don't want. If
you want more than four buttons, try two SelectionBoxes (or similar) together
in a container, where all of the unwanted parts of the widgets are unmanaged.
Alternatively, build your own dialog:
/* Written by Dan Heller. Copyright 1991, O'Reilly && Associates.
* This program is freely distributable without licensing fees and
* is provided without guarantee or warranty expressed or implied.
* This program is -not- in the public domain. This program is
* taken from the Motif Programming Manual, O'Reilly Volume 6.
*/
/* action_area.c -- demonstrate how CreateActionArea() can be used
* in a real application. Create what would otherwise be identified
* as a PromptDialog, only this is of our own creation. As such,
* we provide a TextField widget for input. When the user presses
* Return, the Ok button is activated.
*/
#include <Xm/DialogS.h>
#include <Xm/PushBG.h>
#include <Xm/PushB.h>
#include <Xm/LabelG.h>
#include <Xm/PanedW.h>
#include <Xm/Form.h>
#include <Xm/RowColumn.h>
#include <Xm/TextF.h>
typedef struct {
char *label;
void (*callback)();
caddr_t data;
} ActionAreaItem;
static void
do_dialog(), close_dialog(), activate_cb(),
ok_pushed(), cancel_pushed(), help();
main(argc, argv)
int argc;
char *argv[];
{
Widget toplevel, button;
XtAppContext app;
toplevel = XtVaAppInitialize(&app, "Demos",
NULL, 0, &argc, argv, NULL, NULL);
button = XtVaCreateManagedWidget("Push Me",
xmPushButtonWidgetClass, toplevel, NULL);
XtAddCallback(button, XmNactivateCallback, do_dialog, NULL);
XtRealizeWidget(toplevel);
XtAppMainLoop(app);
}
/* callback routine for "Push Me" button. Actually, this represents
* a function that could be invoked by any arbitrary callback. Here,
* we demonstrate how one can build a standard customized dialog box.
* The control area is created here and the action area is created in
* a separate, generic routine: CreateActionArea().
*/
static void
do_dialog(w, file)
Widget w; /* will act as dialog's parent */
char *file;
{
Widget dialog, pane, rc, label, text_w, action_a;
XmString string;
extern Widget CreateActionArea();
Arg args[10];
static ActionAreaItem action_items[] = {
{ "Ok", ok_pushed, NULL },
{ "Cancel", cancel_pushed, NULL },
{ "Close", close_dialog, NULL },
{ "Help", help, "Help Button" },
};
/* The DialogShell is the Shell for this dialog. Set it up so
* that the "Close" button in the window manager's system menu
* destroys the shell (it only unmaps it by default).
*/
dialog = XtVaCreatePopupShell("dialog",
xmDialogShellWidgetClass, XtParent(w),
XmNtitle, "Dialog Shell", /* give arbitrary title in wm */
XmNdeleteResponse, XmDESTROY, /* system menu "Close" action */
NULL);
/* now that the dialog is created, set the Close button's
* client data, so close_dialog() will know what to destroy.
*/
action_items[2].data = (caddr_t)dialog;
/* Create the paned window as a child of the dialog. This will
* contain the control area (a Form widget) and the action area
* (created by CreateActionArea() using the action_items above).
*/
pane = XtVaCreateWidget("pane", xmPanedWindowWidgetClass, dialog,
XmNsashWidth, 1,
XmNsashHeight, 1,
NULL);
/* create the control area (Form) which contains a
* Label gadget and a List widget.
*/
rc = XtVaCreateWidget("control_area", xmRowColumnWidgetClass, pane, NULL);
string = XmStringCreateLocalized("Type Something:");
XtVaCreateManagedWidget("label", xmLabelGadgetClass, rc,
XmNlabelString, string,
XmNleftAttachment, XmATTACH_FORM,
XmNtopAttachment, XmATTACH_FORM,
NULL);
XmStringFree(string);
text_w = XtVaCreateManagedWidget("text-field",
xmTextFieldWidgetClass, rc, NULL);
/* RowColumn is full -- now manage */
XtManageChild(rc);
/* Set the client data "Ok" and "Cancel" button's callbacks. */
action_items[0].data = (caddr_t)text_w;
action_items[1].data = (caddr_t)text_w;
/* Create the action area -- we don't need the widget it returns. */
action_a = CreateActionArea(pane, action_items, XtNumber(action_items));
/* callback for Return in TextField. Use action_a as client data */
XtAddCallback(text_w, XmNactivateCallback, activate_cb, action_a);
XtManageChild(pane);
XtPopup(dialog, XtGrabNone);
}
/*--------------*/
/* The next four functions are the callback routines for the buttons
* in the action area for the dialog created above. Again, they are
* simple examples, yet they demonstrate the fundamental design approach.
*/
static void
close_dialog(w, shell)
Widget w, shell;
{
XtDestroyWidget(shell);
}
/* The "ok" button was pushed or the user pressed Return */
static void
ok_pushed(w, text_w, cbs)
Widget w, text_w; /* the text widget is the client data */
XmAnyCallbackStruct *cbs;
{
char *text = XmTextFieldGetString(text_w);
printf("String = %s0, text);
XtFree(text);
}
static void
cancel_pushed(w, text_w, cbs)
Widget w, text_w; /* the text field is the client data */
XmAnyCallbackStruct *cbs;
{
/* cancel the whole operation; reset to NULL. */
XmTextFieldSetString(text_w, "");
}
static void
help(w, string)
Widget w;
String string;
{
puts(string);
}
/*--------------*/
/* When Return is pressed in TextField widget, respond by getting
* the designated "default button" in the action area and activate
* it as if the user had selected it.
*/
static void
activate_cb(text_w, client_data, cbs)
Widget text_w; /* user pressed Return in this widget */
XtPointer client_data; /* action_area passed as client data */
XmAnyCallbackStruct *cbs; /* borrow the "event" field from this */
{
Widget dflt, action_area = (Widget)client_data;
XtVaGetValues(action_area, XmNdefaultButton, &dflt, NULL);
if (dflt) /* sanity check -- this better work */
/* make the default button think it got pushed. This causes
* "ok_pushed" to be called, but XtCallActionProc() causes
* the button appear to be activated as if the user selected it.
*/
XtCallActionProc(dflt, "ArmAndActivate", cbs->event, NULL, 0);
}
#define TIGHTNESS 20
Widget
CreateActionArea(parent, actions, num_actions)
Widget parent;
ActionAreaItem *actions;
int num_actions;
{
Widget action_area, widget;
int i;
action_area = XtVaCreateWidget("action_area", xmFormWidgetClass, parent,
XmNfractionBase, TIGHTNESS*num_actions - 1,
XmNleftOffset, 10,
XmNrightOffset, 10,
NULL);
for (i = 0; i < num_actions; i++) {
widget = XtVaCreateManagedWidget(actions[i].label,
xmPushButtonWidgetClass, action_area,
XmNleftAttachment, i? XmATTACH_POSITION : XmATTACH_FORM,
XmNleftPosition, TIGHTNESS*i,
XmNtopAttachment, XmATTACH_FORM,
XmNbottomAttachment, XmATTACH_FORM,
XmNrightAttachment,
i != num_actions-1? XmATTACH_POSITION : XmATTACH_FORM,
XmNrightPosition, TIGHTNESS*i + (TIGHTNESS-1),
XmNshowAsDefault, i == 0,
XmNdefaultButtonShadowThickness, 1,
NULL);
if (actions[i].callback)
XtAddCallback(widget, XmNactivateCallback,
actions[i].callback, actions[i].data);
if (i == 0) {
/* Set the action_area's default button to the first widget
* created (or, make the index a parameter to the function
* or have it be part of the data structure). Also, set the
* pane window constraint for max and min heights so this
* particular pane in the PanedWindow is not resizable.
*/
Dimension height, h;
XtVaGetValues(action_area, XmNmarginHeight, &h, NULL);
XtVaGetValues(widget, XmNheight, &height, NULL);
height += 2 * h;
XtVaSetValues(action_area,
XmNdefaultButton, widget,
XmNpaneMaximum, height,
XmNpaneMinimum, height,
NULL);
}
}
XtManageChild(action_area);
return action_area;
}
-----------------------------------------------------------------------------
Subject: 300) How do I create a "busy working cursor"?
[Last modified: Feb 95]
Answer: - in Baudouin's code (following), the idea is to keep in an array an
up-to-date list of all shells used in the application, and set for all of them
the cursor to a watch or to the default cursor, with the 2 functions provided.
- in Dan Heller's code (later), the idea is to turn on the watch cursor for
the top-level shell only, popup a working window to possibly abort the
callback, and manage some expose events during the callback.
- in the FAQ for comp.windows.x, the idea is to bring a large window on top of
the application, hide all windows below it, and turn on the watch cursor on
this large window. Unmapping the large window resets the default cursor,
mapping it turns on the watch cursor.
Baudouin Raoult (mab@ecmwf.int) wrote:
void my_SetWatchCursor(w)
Widget w;
{
static Cursor watch = NULL;
if(!watch)
watch = XCreateFontCursor(XtDisplay(w),XC_watch);
XDefineCursor(XtDisplay(w),XtWindow(w),watch);
XmUpdateDisplay(w);
}
void my_ResetCursor(w)
Widget w;
{
XUndefineCursor(XtDisplay(w),XtWindow(w));
XmUpdateDisplay(w);
}
Answer: A solution with lots of bells and whistles is
/* Written by Dan Heller. Copyright 1991, O'Reilly && Associates.
* This program is freely distributable without licensing fees and
* is provided without guarantee or warrantee expressed or implied.
* This program is -not- in the public domain.
*/
/* busy.c -- demonstrate how to use a WorkingDialog and to process
* only "important" events. e.g., those that may interrupt the
* task or to repaint widgets for exposure. Set up a simple shell
* and a widget that, when pressed, immediately goes into its own
* loop. First, "lock" the shell so that a timeout cursor is set on
* the shell and pop up a WorkingDialog. Then enter loop ... sleep
* for one second ten times, checking between each interval to see
* if the user clicked the Stop button or if any widgets need to be
* refreshed. Ignore all other events.
*
* main() and get_busy() are stubs that would be replaced by a real
* application; all other functions can be used "as is."
*/
#include <Xm/MessageB.h>
#include <Xm/PushB.h>
#include <X11/cursorfont.h>
Widget shell;
void TimeoutCursors();
Boolean CheckForInterrupt();
main(argc, argv)
int argc;
char *argv[];
{
XtAppContext app;
Widget button;
XmString label;
void get_busy();
shell = XtVaAppInitialize(&app, "Demos",
NULL, 0, &argc, argv, NULL, NULL);
label = XmStringCreateLocalized(
"Boy, is *this* going to take a long time.");
button = XtVaCreateManagedWidget("button",
xmPushButtonWidgetClass, shell,
XmNlabelString, label,
NULL);
XmStringFree(label);
XtAddCallback(button, XmNactivateCallback, get_busy, argv[1]);
XtRealizeWidget(shell);
XtAppMainLoop(app);
}
void
get_busy(widget)
Widget widget;
{
int n;
TimeoutCursors(True, True);
for (n = 0; n < 10; n++) {
sleep(1);
if (CheckForInterrupt()) {
puts("Interrupt!");
break;
}
}
if (n == 10)
puts("done.");
TimeoutCursors(False, NULL);
}
/* The interesting part of the program -- extract and use at will */
static Boolean stopped; /* True when user wants to stop processing */
static Widget dialog; /* WorkingDialog displayed when timed out */
/* timeout_cursors() turns on the "watch" cursor over the application
* to provide feedback for the user that he's going to be waiting
* a while before he can interact with the appliation again.
*/
void
TimeoutCursors(on, interruptable)
int on, interruptable;
{
static int locked;
static Cursor cursor;
extern Widget shell;
XSetWindowAttributes attrs;
Display *dpy = XtDisplay(shell);
XEvent event;
Arg args[1];
XmString str;
extern void stop();
/* "locked" keeps track if we've already called the function.
* This allows recursion and is necessary for most situations.
*/
on? locked++ : locked--;
if (locked > 1 || locked == 1 && on == 0)
return; /* already locked and we're not unlocking */
stopped = False; /* doesn't matter at this point; initialize */
if (!cursor) /* make sure the timeout cursor is initialized */
cursor = XCreateFontCursor(dpy, XC_watch);
/* if "on" is true, then turn on watch cursor, otherwise, return
* the shell's cursor to normal.
*/
attrs.cursor = on? cursor : None;
/* change the main application shell's cursor to be the timeout
* cursor (or to reset it to normal). If other shells exist in
* this application, they will have to be listed here in order
* for them to have timeout cursors too.
*/
XChangeWindowAttributes(dpy, XtWindow(shell), CWCursor, &attrs);
XFlush(dpy);
if (on) {
/* we're timing out, put up a WorkingDialog. If the process
* is interruptable, allow a "Stop" button. Otherwise, remove
* all actions so the user can't stop the processing.
*/
str = XmStringCreateLocalized("Busy. Please Wait.");
XtSetArg(args[0], XmNmessageString, str);
dialog = XmCreateWorkingDialog(shell, "Busy", args, 1);
XmStringFree(str);
XtUnmanageChild(
XmMessageBoxGetChild(dialog, XmDIALOG_OK_BUTTON));
if (interruptable) {
str = XmStringCreateLocalized("Stop");
XtVaSetValues(dialog, XmNcancelLabelString, str, NULL);
XmStringFree(str);
XtAddCallback(dialog, XmNcancelCallback, stop, NULL);
} else
XtUnmanageChild(
XmMessageBoxGetChild(dialog, XmDIALOG_CANCEL_BUTTON));
XtUnmanageChild(
XmMessageBoxGetChild(dialog, XmDIALOG_HELP_BUTTON));
XtManageChild(dialog);
} else {
/* get rid of all button and keyboard events that occured
* during the time out. The user shouldn't have done anything
* during this time, so flush for button and keypress events.
* KeyRelease events are not discarded because accelerators
* require the corresponding release event before normal input
* can continue.
*/
while (XCheckMaskEvent(dpy,
ButtonPressMask | ButtonReleaseMask | ButtonMotionMask
| PointerMotionMask | KeyPressMask, &event)) {
/* do nothing */;
}
XtDestroyWidget(dialog);
}
}
/* User Pressed the "Stop" button in dialog. */
void
stop(dialog)
Widget dialog;
{
stopped = True;
}
Boolean
CheckForInterrupt()
{
extern Widget shell;
Display *dpy = XtDisplay(shell);
Window win = XtWindow(dialog);
XEvent event;
/* Make sure all our requests get to the server */
XFlush(dpy);
/* Let motif process all pending exposure events for us. */
XmUpdateDisplay(shell);
/* Check the event loop for events in the dialog ("Stop"?) */
while (XCheckMaskEvent(dpy,
ButtonPressMask | ButtonReleaseMask | ButtonMotionMask |
PointerMotionMask | KeyPressMask | KeyReleaseMask,
&event)) {
/* got an "interesting" event. */
if (event.xany.window == win)
XtDispatchEvent(&event); /* it's in our dialog.. */
else /* uninteresting event--throw it away and sound bell */
XBell(dpy, 50);
}
return stopped;
}
-----------------------------------------------------------------------------
Subject: 301) Can I use the hourglass that mwm uses?
[Last modified: March 93]
Answer: The hourglass used by mwm is hard-coded into code that is subject to
OSF copyright. In Motif 1.2 though, the bitmaps for this and other things
(information, no_enter, question, warning, working) were made available. The
install process will probably add them to /usr/include/X11/bitmaps.
Otherwise, just use the watch cursor XC_watch of the previous question,
because that has the same semantics.
-----------------------------------------------------------------------------
Subject: 302) What order should the libraries be linked in?
[Last modified: August 92]
Answer: At link time, use the library order -lXm -lXt -lX11. There are two
reasons for this (dbrooks@osf.org):
On most systems, the order matters because the linker won't re-scan a library
once it is done with it. Thus any references to Xlib calls from Xm will
probably be unresolved.
The [other] problem is that there are two VendorShell widgets. A dummy is
provided in the Xt library, but a widget set will rely on its own being
referenced. If you mention Xt first, the linker will choose the wrong one.
Motif code will wrongly assume the Motif VendorShell has been class-
initialized [and will probably crash]. Xaw has a similar problem, but a
softer landing; it only complains about unregistered converters.
-----------------------------------------------------------------------------
Subject: 303) How do I use xmkmf for Motif clients?
[Last modified: July 96]
Answer: This advice comes from dbrooks@osf.org. For another answer, see the
question immediately following this one ("How do I use imake with Motif
2.0?").
There are a number of intractable problems with using X configuration files
and xmkmf, while trying to make it easy to build Motif. Not the least of
these, but one I've never heard mentioned yet, is that the rules for
contructing the names of shared library macros are machine-dependent, and in
the various xxxLib.tmpl files. Do we edit all those files to add definitions
for XMLIB, DEPXMLIB, etc., or do we put a maze of #ifdefs into the Motif.tmpl
file?
Please note that, if you install Motif, it overwrites your installed
Imake.tmpl with one that includes Motif.tmpl and Motif.rules.
With those caveats, I think the following guidelines will help.
David Brooks OSF
Clients in the X11R5 release use the xmkmf command to build Makefiles. In
general, the xmkmf command cannot be used for Motif clients, because of the
need to consider the UseInstalledMotif flag separately. Since xmkmf is a
simple script that calls imake, it is easy to construct the proper call to
imake using the following rules.
In the following, replace {MTOP} by the toplevel directory with the Motif
source tree, and {XTOP} by the toplevel ("mit") directory with the X source.
It is assumed that the directory containing your installed imake is in your
PATH.
When needed, the imake variables XTop and MTop are normally set in your
site.def (to {XTOP} amd {MTOP} respectively); however they may also be set
with additional -D arguments to imake.
1. With both X and Motif in their source trees, ensure the imake variables
XTop and MTop are set, and use:
${XTOP}/config/imake -I{MTOP}/config
2. With Motif in its source tree, and X installed, ensure MTop is set, and
use:
imake -I{MTOP}/config -DUseInstalled
3. With both Motif and X installed, and a nonstandard ProjectRoot (see
site.def for an explanation of this), use:
imake -DUseInstalled -DUseInstalledMotif -I{ProjectRoot}/lib/X11/config
or, if the configuration files are in /usr/lib/X11/config:
imake -DUseInstalled -DUseInstalledMotif -I/usr/lib/X11/config
[Thanks to Paul DuBois (dubois@primate.wisc.edu) for correcting this.]
To build a simple Imakefile, remember to include lines like this:
LOCAL_LIBRARIES = XmClientLibs
DEPLIBS = XmClientDepLibs
Or, for a client that uses uil/mrm, replace these by MrmClientLibs and
MrmClientDepLibs, and also use:
MSimpleUilTarget(program)
to build the client and uid file. Look at the demos for more examples.
And Paul Howell <grue@engin.umich.edu> added:
i did this, calling the new script "xmmkmf". It passes both -DUseInstalled
and -DUseInstalledMotif.
and i modified the stock R5 Imake.tmpl to do this:
#include <Project.tmpl>
#ifdef UseInstalledMotif
#include <Motif.tmpl>
#endif
#include <Imake.rules>
#ifdef UseInstalledMotif
#include <Motif.rules>
#endif
the result was something that does both athena and motif rules. and it really
works, just that easy!
-----------------------------------------------------------------------------
Subject: 304) How do I use imake with Motif 2.0?
[Last modified: July 96]
Answer: Paul DuBois (dubois@primate.wisc.edu), the author of the O'Reilly and
Associates book, Software Portability with imake, recently wrote some notes on
the use of imake to configure Motif (2.0). It has some discussion on the roles
of UseInstalled and UseInstalledMotif, for instance, which seem to be murky to
many people. The document is available at:
http://www.primate.wisc.edu/software/imake-stuff
-----------------------------------------------------------------------------
Subject: 305) How do I make context sensitive help? The Motif Style Guide
says that an application must initiate context-sensitive help by changing the
shape of the pointer to the question pointer. When the user moves the pointer
to the component help is wanted on and presses BSelect, any available context
sensitive help for the component must be presented, and the pointer reverts
from the question pointer.
[Last modified: August 92]
Answer: A widget that gives context sensitive help would place this help in
the XmNhelpCallback function. To trigger this function: (from Martin G C
Davies, mgcd@se.alcbel.be)
I use the following callback that is called when the "On Context" help
pulldown menu is selected. It does the arrow bit and calls the help callbacks
for the widget. It also zips up the widget tree looking for help if needs be.
I don't restrict the arrows motion so I can get help on dialog boxes. No
prizes for guessing what "popup_message" does.
static void ContextHelp(
Widget w ,
Opaque * tag ,
XmAnyCallbackStruct * callback_struct
)
{
static Cursor context_cursor = NULL ;
Widget context_widget ;
if ( context_cursor == NULL )
context_cursor = XCreateFontCursor( display, XC_question_arrow ) ;
context_widget = XmTrackingLocate( top_level_widget,
context_cursor, FALSE ) ;
if ( context_widget != NULL ) /* otherwise its not a widget */
{
XmAnyCallbackStruct cb ;
cb.reason = XmCR_HELP ;
cb.event = callback_struct->event ;
/*
* If there's no help at this widget we'll track back
up the hierarchy trying to find some.
*/
do
{
if ( ( XtHasCallbacks( context_widget, XmNhelpCallback ) ==
XtCallbackHasSome ) )
{
XtCallCallbacks( context_widget, XmNhelpCallback, & cb ) ;
return ;
}
else
context_widget = XtParent( context_widget ) ;
} while ( context_widget != NULL ) ;
}
popup_message( "No context-sensitive help found0or the selected object." ) ;
}
Dave Bonnett suggested, to use the following translations for XmText (and
XmTextField) widgets to get the same help with key strokes, and to provide an
accelerator label in the Context help menu entry.
MyApp*XmText*translations: #override\n\
<Key>F1: Help()
MyApp*Help_menu*Contextual Help.acceleratorText: F1
MyApp*defaultVirtualBindings: osfBackSpace : <Key>Delete\n\
osfRight : <Key>Right\n\
osfLeft : <Key>Left\n\
osfUp : <Key>Up\n\
osfHelp : <Key>F1\n\
osfDown : <Key>Down
-----------------------------------------------------------------------------
Subject: 306) How do I debug a modal interaction?
When an application crashes in a modal section (such as in a modal dialog, a
menu or when a drag and drop is in action), I cannot access the debugger.
[Last modified: January 1993]
Answer: Run the debugger on one display while the application writes to
another display.
-----------------------------------------------------------------------------
Subject: 307) Why can't I install my own colormap using XInstallColormap?
[Last modified: Nov 96]
Answer: You shouldn't install the colormap yourself using XInstallColormap.
See the ICCCM document for all the reasons. Instead put the colormap as an
argument on the Shell widget and the window manager will take care of this.
When the colormap is installed, unless you have a display with multiple
colormaps, the other windows will go "technicolor" and there is no way around
this problem.
Thanks to Doug Rand (drand@sgi.com)
Kenton Lee (http://www.rahul.net/kenton/) adds: Use XtSetWMColormapWindows()
to specify non-default colormaps.
-----------------------------------------------------------------------------
Subject: 308) How do I install a private colormap?
[Last modified: Jan 96]
Answer: Mark Buser (buser@tartan.com) writes: If you find that your
XAllocNamedColor is failing or XpmCreatePixmapFromData is dieing from
XpmColorFaileds, you may have exhausted the number of colormap entries. One
way to install a new colormap is the following:
Toplevel = XtVaAppInitialize ( &app, ...
dpy = XtDisplay (Toplevel);
cmap = DefaultColormapOfScreen ( XtScreen( Toplevel) );
/* Detect color errors due to colormap depletion */
if (colors_depleted) {
cmap = XCopyColormapAndFree ( dpy, cmap );
/* Run through color allocation again to see if ok now */
}
/* Install colormap into toplevel widget. This must be done
** before any child widgets are created.
*/
XtVaSetValues ( Toplevel, XmNcolormap, cmap, NULL);
/* Create any children of toplevel, they will inherit new colormap */
This is only one way to go, there are other possibilities, but this seems to
be the simplest.
-----------------------------------------------------------------------------
Subject: 309) How do I get correct shadow colors to match other color
changes?
[Last modified: Sept 95]
Answer: Thanks to Craig MacFarlane (craigm@chateau-rouge.ICS.UCI.EDU) for the
following explanation and code:
You have to make a call to calculate the new shadow colors. The trick is
actually getting a value of type Pixel when all you have is the string "Blue".
I use the XtConvertAndStore() function to convert from a char * to a Pixel.
For example:
char *color = "blue";
XrmValue color_value, pixel_value;
Pixel background;
color_value.size = strlen(color);
color_value.addr = (XtPointer) color;
pixel_value.size = sizeof(Pixel);
pixel_value.addr = (XtPointer) 0;
result = XtConvertAndStore(widget,
XtRString, &color_value,
XtRPixel, &pixel_value);
background = (*(Pixel *)pixel_value.addr);
You can then use the pixel value obtained by XtConvertAndStore() in the
XmGetColors call. XmGetColors calculates appropriate foreground, topshadow,
bottomshadow, and select colors for the given background. e.g.
XmGetColors(screen,
DefaultColormap(display_id, DefaultScreen(display_id)),
background,
&foreground, &topshadow, &bottomshadow, &select);
Then it's trivial to set the shadow colors at the same time you set the
foreground and background colors. For example:
XtVaSetValues(widget,
XmNforeground, foreground,
XmNbackground, background,
XmNarmColor, select,
XmNtopShadowColor, topshadow,
XmNbottomShadowColor, bottomshadow,
NULL);
You'll get asthetically pleasing colors every time. :)
Wolfram Gries <1gries@informatik.uni-hamburg.de> adds:
The function XmChangeColor() takes a Widget and a Pixel-value for the new
background-color and does the calculation of the new shadow-colors on its own.
But it seems to me that this function is rather slow, so if you often change
the color of your widgets, the XmGetColors()/XmSetColors() approach might be
better.
-----------------------------------------------------------------------------
Subject: 310) What color algorithm does Motif use? I am told that Motif uses
some sort of algorithm that will take a single color that is defined for the
"background" and scale it so that the widget remains discriminable from the
background, etc. What is the algorithm?
[Last modified: Oct 94]
Answer: Chris Flatters (cflatter@nrao.edu) writes: Shiz Kobara's book "Visual
Design with OSF/Motif", Addison Wesley, 1991, ISBN 0-201-56320-7) is a good
source for information of this sort. I haven't seen it in bookshops for a
while so it may have gone out of print (which would be a pity). In essence
each widget has 4 colours which, to first order, are
background
select (background * 85%)
top shadow (background * 150%)
bottom shadow (background * 50%)
An additional correction may be applied to the hues of the calculated colours
if any of the RGB values saturates. The algorithm works best if the brightest
of the RGB components lies in the range 155-175 (on a scale of 0-255). The
top shadow becomes darker than the background for light background colours
which does not lead to a particularly pleasing effect.
-----------------------------------------------------------------------------
Subject: 311) How can you access the superclass widget from which Motif
convenience dialogs are subclassed?
[Last modified: Oct 94]
Answer: Kim Frei (uunet!ask.uniras.dk!kimf) wrote: If you are using Motif 1.2,
read about XmTemplateDialog.
-----------------------------------------------------------------------------
Subject: 312) Can the Motif 2.0 Notebook widget display non-rectangular "file
tabs"? Is it possible to use the Shape extension to fiddle with the shape of
the major tabs (XmPushButtons right now) to get non-rectangular buttons, going
for that "file tab" look?
[Last modified: May 95]
Answer: Vania Joloboff <uunet!gr.osf.org!vania> wrote:
On the Motif 2.0* CD-ROM, in the demos directory, there is a library of
additional widgets lib/Exm. Among the widgets, there is a ExmTabButton
especially designed to fit within a Notebook. It has a smooth shape like real
tabs in folders.
It also a good example on how to use the new traits and the Xme API for widget
writers.
(Thanks to Ken Lee, http://www.rahul.net/kenton/, for a correction here.)
-----------------------------------------------------------------------------
Subject: 313) How does the clipboard mechanism work?
[Last modified: Dec 94]
A. Doug Rand <drand@sgi.com> writes:
Basically there are two selections CLIPBOARD_MANAGER and CLIPBOARD which are
used. The Motif clipboard is not a clipboard manager, but xclipboard, or a
more functional clipboard client would be. The newest ICCCM (2.0) spells this
out.
The basic process is that the clipboard manager:
1) Check to see if CLIPBOARD_MANAGER is owned by anyone, abort if it is.
2) Assert ownership of CLIPBOARD_MANAGER and CLIPBOARD
3) When the CLIPBOARD selection is lost, query new owner for data and then
retake ownership of CLIPBOARD
#3 is done until the application exists. What you do with the data is up to
the application.
-----------------------------------------------------------------------------
Subject: 314) Why does the xyz application core dump when I cut and paste?
Answer: Application crashes when text is cut and pasted into an XmText widget
may occur with statically linked executables linked with X11R5 libraries under
SunOS. For example, a Netscape README file says:
The SunOS 4.1 [Netscape 0.94] distribution also includes a directory called
"nls". This directory is a standard part of the MIT X11R5 distribution, but
is not included with OpenWindows 3.0 or earlier. We have linked Netscape
against the MIT R5 libraries because they are less buggy in general; however,
they have one rather serious bug, which is that if this "nls" directory does
not exist, the program will dump core any time you try to paste into a text
field!
So, if you don't have the "nls" directory on your system, you will need to
install it first. The usual place is /usr/lib/X11/nls, but you can put it
anywhere: just point the $XNLSPATH environment variable at it.
Some sites don't have their X libraries installed in /usr/lib/X11/. This
doesn't matter. You either need to put the nls directory in /usr/lib/X11/, or
every user will need to set this environment variable.
So, for example, we do:
setenv XNLSPATH /usr/local/x11r5/lib/X11/nls
since our X11R5 is not installed in the default location.
-----------------------------------------------------------------------------
Subject: 315) Why is XtWindow(widget) == 0?
[Last modified: Oct 95]
Answer: The window is not created (and is NULL) until the widget is realized.
In general, using XtWindow() is a bad idea. In most cases, you can create
more robust code by subclassing the widget and putting your window code in new
wiget class methods.
Ken Lee
-----------------------------------------------------------------------------
Subject: 316) How do I debug X protocol errors (e.g., BadWindow, BadMatch) in
Motif applications?
[Last modified: Jun 98]
Answer: For a general tutorial on X protocol errors, see:
http://www.rahul.net/kenton/perrors.html
Here are two common problems. First, if you get a BadWindow error showing a
0x0 window ID, you're probably calling XtWindow() on a widget that is not
realized. See the previous subject.
Second, a BadMatch error often indicates that the depth of a window or a
pixmap is not correct. You could be using a depth 1 pixmap when you should be
using a pixmap with the depth of the associated window. Or, you could be
creating a new shell with a depth that does not match its visual type or
colormap.
Ken Lee
-----------------------------------------------------------------------------
Subject: 317) Why doesn't XtNameToWidget (widget, "MyName") work?
[Last modified: Apr 95]
Answer: The second argument must be a qualified specification (like a resource
specification). In most cases, you'll use something like "*MyName". The
leading '*' is required.
Ken Lee
-----------------------------------------------------------------------------
Subject: 318) Why does my callback's client data structure contain incorrect
values when the callback is called? I created a structure and used a pointer
to it as callback client data.
[Last modified: Apr 95]
Answer: If your structure is declared as automatic, the callback will probably
not be executed within the structure's scope, so the pointer to the structure
will become invalid. You can avoid this problem by declaring your structure
external or by allocating with malloc or (in C++) new.
Ken Lee
-----------------------------------------------------------------------------
Subject: 319) How can an application manage events on multiple displays?
[Last modified: May 95]
Answer: Just put multiple display pointers into one application context. (You
normally specify which application context as an argument to XtOpenDisplay()).
XtAppNextEvent() and XtAppMainLoop() automatically poll all displays in the
application context.
Ken Lee
-----------------------------------------------------------------------------
Subject: 320) Can a Motif application create windows on mutiple screens (on a
multi-screen workstation)?
[Last modified: Sep 97]
Answer: Multiple screens is simpler than multiple displays, since one X server
controls all of the screens. Simply specify the XmNscreen resource when you
create your top level (or other) shell widget and the X Toolkit will create
the shell on that screen. You should generally also explicitly set your
XmNcolormap, XmNdepth, and XmNvisual resources for the new shell, since the
defaults may not be valid on the second screen.
Ken Lee
-----------------------------------------------------------------------------
Subject: 321) Why do I get "Error: attempt to add non-widget child "dsm" to
parent"?
[Last modified: May 95]
Answer: Most likely, you are linking your libraries in the wrong order. You
must link -lXm *before* -lXt.
Ken Lee
Ken Sall (ksall@cen.com) adds: This same error occurs if you combine Motif and
Athena widgets in the same application. If you link with "-lXaw" before "-
lXm", you get the runtime error. However, if you switch the order of the two
libraries, there is no problem. For example:
cc mothena.c -o mothena -lXm -lXaw -lXt -lXmu -lX11
-----------------------------------------------------------------------------
Subject: 322) Why do I get link errors about "XShape" symbols?
[Last modified: May 95]
Answer: You must link with the X extensions library, -lXext, after any widget
libraries. For example,
cc -o myapp myapp.o -lXm -lXt -lXext -lX11
Ken Lee
-----------------------------------------------------------------------------
Subject: 323) Why do I get link errors about "ICE" and "SM" symbols?
[Last modified: Sep 97]
Answer: You must link with the the X ICE and/or SM libraries. For example,
cc -o myapp myapp.o -lXm -lXt -lXext -lICE -lSM -lX11
Ken Lee
-----------------------------------------------------------------------------
Subject: 324) Why does my X11R6 program crash with undefined symbol
"LowerCase"?
[Last modified: May 95]
Answer: If you are using Motif version 1.1.[123], then the problem may be a
failure to set MotifBC to YES in your site.def.
Thanks to Geoffrey Leach, geoff@netcom.com
-----------------------------------------------------------------------------
Subject: 325) How do I programatically control xwd to dump a specific window?
I need a non-interactive way to tell xwd what X window to make an image of...
NOT by the traditional point-and-click method.
[Last modified: July 95]
Answer: Ken Sall (ksall@cen.com) wrote:
1. Get the window id of the toplevel shell widget using the "XtWindow"
function.
2. Invoke "xwd" from the program that has access to the window id, such as:
Window dumpId; /* returned from XtWindow */
sprintf (cmd_string, "xwd -frame -out tmp.xwd -id 0x%x", dumpId);
system (cmd_string);
-----------------------------------------------------------------------------
Subject: 326) How can I display an xwd in a window (without using xwud)?
[Last modified: Sept 95]
Answer:
1. read the xwd file into an XImage
2. create a pixmap and XPutImage the image into the pixmap
3. use the pixmap as the XmNlabelPixmap of a label widget
Ken Lee
-----------------------------------------------------------------------------
Subject: 327) Can I write a multi-threaded Motif application?
[Last modified: May 97]
Answer: Motif 2.1 can be compiled to be thread-safe (if libX11 and libXt are
also compiled to be thread-safe).
Motif releases prior to Motif 2.1 were not thread-safe. In these releases,
you can use Motif from one thread and do other things in other threads but you
cannot call Motif functions from more than one thread.
Try looking in the X FAQ for information on threads:
http://www.cis.ohio-state.edu/hypertext/faq/usenet/x-faq/top.html
ftp://ftp.x.org/contrib/faqs/FAQ
Ken Lee
-----------------------------------------------------------------------------
Subject: 328) How can I dump my widget instance tree in a way that reflects
the hierarchy?
[Last modified: July 97]
Answer: Jeremy Jameson (jameson@drmail.dr.att.com) posted this code to c.w.x.m
in 5/95.
[Note: this code does not consider popup children, which are not listed in
the XmNchildren array. To find those, you have to peek at the popup_list in
core widget record. - K.Lee 7/97]
/*******************************************************************************
* dumpWidgetTree( Widget w )
*
* This function will recursively descend throught the Widget tree
* and print the children and their pointer addresses.
*
* Jeremy Jameson 5/17/95
*
*******************************************************************************/
static void dumpWidgetTree( Widget w )
{
WidgetList list = NULL;
Cardinal num_children = 0;
int i;
static int n = 0;
Widget child;
static char* indent =
"-----------------------------------------------------------------------------";
char tmp[256];
*tmp = ' ';
if ( n >= strlen( indent ) +1 )
{
printf(
"ERROR:Widget tree is too deep, not enough indent string ( < %d )!\n",
n );
n = 0;
return;
}
strncpy( tmp, indent, n );
tmp[n] = ' ';
printf( "%s> Dumping widget tree of %s - %#x \n", tmp, XtName( w ), w );
if ( ! XtIsComposite( w ) )
{
printf(
"%s> %s is not a subclass of Composite and therefore has no children\n",
tmp, XtName( w ) );
return;
}
XtVaGetValues( w,
XmNchildren, &list,
XmNnumChildren, &num_children,
NULL );
printf( "%s> %s has %d %s\n", tmp, XtName( w ),
num_children, num_children == 1 ? "child" : "children" );
for ( i = 1; i <= num_children; i++ )
{
child = list[i-1];
printf( "%s> child %2d %20s \t (%#x)\n", tmp, i, XtName( child ), child );
}
printf( "\n" );
for ( i = 1; i <= num_children; i++ )
{
child = list[i-1];
n += 3;
dumpWidgetTree( child );
n -= 3;
}
printf( "\n" );
}
-----------------------------------------------------------------------------
Subject: 329) How do I get the events for gadgets? Or the name of the gadget?
[Last modified: July 96]
Answer: Get events from the gadget's parent. Ken Lee
A related question is "How the name of a gadget an event is directed to?"
Daniel Dardailler (daniel@x.org) writes:
Motif 2.0 provides a XmObjectAtPoint public function that support this
functionality. For earlier version, something like the undocumented
_XmInputInGadget( wid, x, y ) should do it.
_XmInputInGadget
Given a composite widget and an (x, y) coordinate, see if the
(x, y) lies within one of the gadgets contained within the
composite. Return the gadget if found, otherwise return NULL.
-----------------------------------------------------------------------------
Subject: 330) Can I set the foreground and background colors of gadgets
(e.g., convenience dialog buttons)?
[Last modified: Nov 96]
Answer: Not in Motif 1.x. Gadgets don't have their own colors, they use those
of their parents. Notice that Motif's convenience dialogs generally use label
gadgets, not widgets, so you cannot customize the colors of individual
buttons.
Beginning in Motif 2.0, gadgets do have their own color resources.
Ken Lee
-----------------------------------------------------------------------------
Subject: 331) Can I use a gadget as the parent of a dialog shell?
[Last modified: Dec 97]
Answer: No. The Core widget class contains the functionality for popup
children. Since the Gadget class is not a subclass of Core, gadgets cannot
have popup children (like dialogs).
-----------------------------------------------------------------------------
Subject: 332) Which other widget features do gadgets lack?
[Last modified: Dec 97]
Answer: Here's a list from Asente & Swick (p. 397). Note that many of these
restrictions are primarily of interest to widget (and gadget) writers, not to
application writers.
1. gadgets have no background or border colors or pixmaps
2. gadgets cannot have event handlers
3. gadgets have no translations, accelerators, or actions
4. gadgets cannot have pop-up children
5. gadgets cannot do grabs
6. gadgets cannot redirect the Intrincis keyboard focus or take the X focus
7. gadgets cannot own or request selections
8. gadgets do not need to be and cannot be realized
9. gadgets cannot have their window, display, or screen queried (but
there are separate functions for computing these)
10. gadgets have no stacking order
-----------------------------------------------------------------------------
Subject: 333) Where can I get the xmon or xscope programs to trace my X
protocol?
[Last modified: Mar 96]
Answer: Both are included in the contrib section of X11R5:
ftp://ftp.x.org/pub/R5/
Xmon is also available at: ftp://ftp.x.org/contrib/devel_tools/ and
ftp://ftp.crl.research.digital.com/pub/X11/contrib/devel_tools/
Ken Lee
-----------------------------------------------------------------------------
Subject: 334) What does the error "Couldn't find per display information"
mean?
[Last modified: Mar 96]
Answer: Xt often needs information about the current X display. It generates
this error when it couldn't find the display pointer. Common causes
applications accidentally destroying widgets twice or trying to generate fake,
incomplete events with XSendEvent().
Ken Lee
-----------------------------------------------------------------------------
Subject: 335) Can I set widget fallback resources after I've called
XtAppInitialize()?
[Last modified: Mar 96]
Answer: No. Fallbacks are only checked when displays are initialized.
Ken Lee
-----------------------------------------------------------------------------
Subject: 336) Can I use the newline character in widget names?
[Last modified: Mar 96]
Answer: No. Widget names are designed to be used in resource specifications.
The Xlib resource file syntax says the only alphanumeric characters (plus '-'
and '_') may be used in a resource component name. If you want more than one
line of text in a label widget, set the XmNlabelString resource.
Ken Lee
-----------------------------------------------------------------------------
Subject: 337) Is anybody out there selling Windows95 look-alike widgets? Why
isn't there a Widget builder for Motif/X yet? Something like OCX (I believe on
Windows95).
[Last modified: Mar 96]
Answer: David B. Lewis (dbl%craft@uunet.uu.net) writes:
None that I know of. There are similar widgets available in Motif 2.0. There
are similar widgets available in the ICS EnhancementPak.
[For the second part of the question...] Because it's very hard to do. I don't
know what OCX is, but I can't imagine that the technology is so much better
than that used in Xt that it's possible to write something to generate real
code. It's trivial, of course, to generate the framework for a widget given
only its name, superclass, and resources; but everything else is real code.
-----------------------------------------------------------------------------
Subject: 338) How can I convert my OLIT programs to the Motif look & feel?
[Last modified: July 96]
Answer: Mark Fresolone (mjf@mjm.com) writes: There are a number of translator
products on the market which translate OLIT source code or DevGuide builder
files into Motif source code and builder files.
In 1995, MJM Software (Melillo Consulting Inc.) released the MoOLIT 5.1
toolkit, which allows one to simply re-compile Sun or UnixWare OLIT programs,
and have them be switchable between the OPENLOOK and Motif look and feels.
MoOLIT 5.1 is available on most popular UNIX platforms. More information is
available at:
http://www.mjm.com/Products/MoOLIT
-----------------------------------------------------------------------------
Subject: 339) What does this mean: Warning: Cannot find callback list in
XtAddCallback?
[Last modified: July 96]
Answer: It means that you gave an invalid callback name to XtAddCallback,
e.g., using XmNactivateCallback when the widget does not have a callback with
that name.
Ken Lee
-----------------------------------------------------------------------------
Subject: 340) If a single widget has multiple callback functions, are they
all executed? If so, in what order?
[Last modified: Nov 96]
Answer: Yes, they are all executed. The order, however, is not defined by the
X Toolkit specifications. If you really want a certain order, you should
register a single callback function and have it call your other functions in
the order you want.
Ken Lee
-----------------------------------------------------------------------------
Subject: 341) Why are some widgets still visible after I call
XtDestroyWidget() on them?
[Last modified: Nov 96]
Answer: To avoid memory corruption problems, the X Toolkit uses a 2 phase
destroy process. When you call XtDestroyWidget(), the widgets are not really
destroyed until after you return to the Xt main loop. Until then, the widget
will behave (mostly) as if they were not destroyed. If this is a problem, you
should unmanage them as well (you can safely unmanage them after you destroy
them and before you return to the main loop).
Ken Lee
Note: The details of the two-phase destruction are described on the
XtCreateWidget(3Xt)/XtDestroyWidget(3Xt) man page. - ksall@cen.com
-----------------------------------------------------------------------------
Subject: 342) If I call XtGetValues on a resource that does not exist for a
given widget, what value is returned?
[Last modified: Nov 96]
Answer: No value is returned. Your return variable is not modified. If it
was uninitialized (i.e., garbage) before the call to XtGetValues, it will
remain uninitialized.
Ken Lee
-----------------------------------------------------------------------------
Subject: 343) Can I reparent a widget (change its parent)?
[Last modified: Aug 97]
Answer: Xt does not support reparenting of widgets within the widget
hierarchy. This would complicate the hierarchical resource model. You can
destroy the old hierarchy and create a new one. On most systems, this is
pretty fast for reasonably sized widget hierarchies.
Note, however, that X11R6.3 provides an "application group" extension that
allows one X client to act as the root of another X client's window hierarchy.
See the X11R6.3 documentation for more details.
Ken Lee
-----------------------------------------------------------------------------
Subject: 344) Are there any "year 2000" issues within Motif?
[Last modified: Jun 98]
Answer: According to
http://www.camb.opengroup.org/tech/desktop/faq/y2k.htm
Dear Customer:
The Open Group has completed a review of Motif (OSF/Motif) and the X Window
System with regard to Year 2000 issues, and has determined that Motif
(versions 1.0 through 2.1) and X Window System (X11 Releases 5 through 6.4)
source code, as provided directly by The Open Group (or, previously provided
by Open Software Foundation, Inc.; or X Consortium in the case of X Window
System) does not contain any date-dependent source code. The arrival of the
year 2000 should have no effect on the operation of Motif or X Window System
source code.
Please note, however, that Motif & X Window System object code or
applications, or derivative works thereof, which would have been provided to
you by a third party, are not covered by the above statement. You are hereby
referred to your supplier for statements regarding Year 2000 issues for such
third-party products.
Very truly yours,
The Open Group
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Subject: 345) Can I suppress or customize Motif warning and error messages?
[Last modified: Aug 97]
Answer: A better idea is usually to fix problems indicated by the messages.
If you must, Motif justs uses Xt's message system which can be customized with
XtAppSetWarningHandler and XtAppSetErrorHandler.
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Subject: 346) TOPIC: Motif FAQ HISTORY and ACKNOWLEDGEMENTS
[Last modified: April 97]
Answer:
History:
-------
November 89 to July 93: FAQ was maintained by Jan Newmarch
(jan@ise.canberra.edu.au)
July 93 to August 94: FAQ was maintained by Brian Dealy
(dealy@c3i.saic.com)
Sept. 94 to April 97: FAQ was maintained by Ken Sall
(ksall@cen.com)
beginning April 97: FAQ was maintained by Kenton Lee
(http://www.rahul.net/kenton/)
Acknowledgments:
----------------
This list was compiled using questions and answers posed to
comp.windows.x.motif and motif-talk. Some information was excerpted from the
comp.windows.x FAQ. To all who contributed one way or the other, thanks! We
try to give individual references, but you may recognize something
(jan@ise.canberra.edu.au)
July 93 to August 94: FAQ was maintained by Brian Dealy
(dealy@c3i.saic.com)
Sept. 94 to April 97: FAQ was maintained by Ken Sall
(ksall@cen.com)
beginning April 97: FAQ was maintained by Kenton Lee
(http://www.rahul.net/kenton/)
Acknowledgments:
----------------
This list was compiled using questions and answers posed to
comp.windows.x.motif and motif-talk. Some information was excerpted from the
comp.windows.x FAQ. To all who contributed one way or the other, thanks! We
try to give individual references, but you may recognize something uncredited
as your contribution. If we've mangled the words (or, heaven forbid, the code)
too much, let the current maintainer know.
NOTE: If you are a two-or-more-time contributor to this FAQ and you have a WWW
personal home page which you'd like to have listed, see the subject: "Which X
and Motif developers have their own home page URLs?"
Jan Newmarch, Information Science and Engineering,
University of Canberra, PO Box 1, Belconnen, Act 2616
Australia. Tel: (Aust) 6-2522422. Fax: (Aust) 6-2522999
ACSnet: jan@ise.canberra.edu.au
ARPA: jan%ise.canberra.edu.au@uunet.uu.net
UUCP: {uunet,ukc}!munnari!ise.canberra.edu.au!jan
JANET: jan%au.edu.canberra.ise@EAN-RELAY
Jan Newmarch maintained this FAQ for a long time and has really helped a great
many of us by providing this valuable service. He deserves a big round of
applause for his efforts. I use this resource all the time and it has saved
me countless hours with manuals and source code trying to relearn what others
have already discovered. Jan`s efforts are gratefully acknowledged here.
Brian Dealy, SAIC
dealy@c3i.saic.com
Likewise, Brian Dealy of SAIC did an admirable job taking over the Motif FAQ
from Jan. A considerable amount of information was added during his tenure and
we greatly appreciate Brian's work on the FAQ, as well as his efforts in
maintaining the comp.windows.x.motif newsgroup reflector, for the good of all
Motif-dom.
Ken Sall
ksall@cen.com
Tel: (301) 953-3330 FAX: (301) 953-2368
Century Computing, Inc.
http://www.cen.com/
My thanks to Ken Sall for maintaining the FAQ for 1994-1997. During Ken's
tenure the FAQ more than doubled in size. Ken was one of the first FAQ
maintainers to change all ftp references to URLs and to incorporate http URLs
thoroughout the FAQ.
Kenton Lee
X/Motif Consultant
kenton@nojunk.rahul.net
http://www.rahul.net/kenton/
The end.
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