sxb@sequoia.cray.com (Stephen Behling) (03/01/91)
I am just starting my Motif programming after a few years playing
around with Xlib. I am finding it a lot of fun, but a bug I have
is causing me pain. I've tried everything I can think of for a
couple days now...and now I need help.
I get a segmentation fault core dump when I try to use a
WarningDialog from a widget, but only if I first use a WarningDialog
from a second widget.
SITUATION: I create a Form widget in an application shell. In
the Form I create a MenuBar and a DrawingArea. In the MenuBar I create
six CascadeButtons with PullDownMenus that have some PushButtons.
All this works, and the Callbacks are fine. Now I am starting to
add dialog widgets to the PushButtons. On one PushButton I create
a FileSelectionDialog and on another, I create a SelectionDialog.
For each of these Dialogs, I set the mustMatch parameter to True
and add a noMatchCallback. In the noMatchCallback, I create a
WarningDialog with just the OK button (by unmanaging the others).
The following causes the bug:
PushButton to create SelectionDialog.
Have bad selection so noMatchCallback is called
Create the WarningDialog
Click OK on the WarningDialog
Either make good selection or cancel.
(Call XtDestroyWidget for WarningDialog widget and
then the SelectionDialog in either case).
PushButton to create FileSelectionDialog
Have bad selection so noMatchCallback is called
(this is a different nomatch callback)
Create the WarningDialog
...here I get....
Warning: null child passed to XtManageChildren
Segmentation fault (core dumped)
I can do it slightly differently and get...
Warning: no ext to pop
Segmentation fault (core dumped)
--------
-------- Anybody have any ideas yet? Remember, I'm brand new to
-------- Motif, so I may be doing something obviously dumb
--------
SYSTEM: Sun sparc 4.1-GFX- with Motif 1.1
THE CODE FRAGMENTS ARE:
To create the FileSelectionDialog......
n = 0;
XtSetArg(args[n], XmNx, 50); n++;
XtSetArg(args[n], XmNy, MENU_BAR_HEIGHT + 4); n++;
XtSetArg(args[n], XmNmustMatch, True); n++;
XtSetArg(args[n], XmNapplyLabelString,
XmStringCreateLtoR("Apply Filter",
XmSTRING_DEFAULT_CHARSET)); n++;
XtSetArg(args[n], XmNdialogStyle, XmDIALOG_FULL_APPLICATION_MODAL); n++;
file_box = XmCreateFileSelectionDialog(main_window, "File Select",
args, n);
tmp_widget = XmFileSelectionBoxGetChild(file_box, XmDIALOG_HELP_BUTTON);
XtUnmanageChild(tmp_widget);
XtAddCallback(file_box, XmNcancelCallback,Cancel3CB,NULL);
XtAddCallback(file_box, XmNokCallback,OpenOKCB,NULL);
XtAddCallback(file_box, XmNnoMatchCallback,NomatchOpenCB,NULL);
XtManageChild(file_box);
and for the SelectionDialog....
n = 0;
XtSetArg(args[n], XmNlistItems, item); n++;
XtSetArg(args[n], XmNlistItemCount, m); n++;
XtSetArg(args[n], XmNlistVisibleItemCount, 15); n++;
XtSetArg(args[n], XmNmustMatch, True); n++;
XtSetArg(args[n], XmNdialogStyle, XmDIALOG_FULL_APPLICATION_MODAL); n++;
XtSetArg(args[n], XmNautoUnmanage, False); n++;
my_widget = XmCreateSelectionDialog( main_window, "ChooseContour",
args, n);
tmp_widget = XmSelectionBoxGetChild(my_widget, XmDIALOG_HELP_BUTTON);
XtUnmanageChild(tmp_widget);
tmp_widget = XmSelectionBoxGetChild(my_widget, XmDIALOG_APPLY_BUTTON);
XtUnmanageChild(tmp_widget);
XtAddCallback(my_widget, XmNcancelCallback,Cancel2CB,NULL);
XtAddCallback(my_widget, XmNokCallback,ConOKCB,NULL);
XtAddCallback(my_widget, XmNnoMatchCallback,NomatchChooseConCB,NULL);
XtManageChild(my_widget);
USING DBX I GET: (from the Warning: no ext to pop case...)
Reading symbolic information...
Read 2603 symbols
program terminated by signal SEGV (no mapping at the fault address)
(dbx) where
_XmPopWidgetExtData() at 0x779dc
`PushBG`SetValuesPosthook() at 0x868d4
SetValuesLeafWrapper() at 0x784f8
CallConstraintSetValues() at 0xf7718268
XtSetValues() at 0xf77184ac
_XmBulletinBoardSetDynDefaultButton() at 0x7d5a4
_XmBulletinBoardFocusMoved() at 0x7cee8
_XmFileSelectionBoxFocusMoved() at 0xca38
_XtCallCallbacks() at 0xf7700998
XtCallCallbackList() at 0xf7700c04
_XmCallFocusMoved() at 0x71170
_XmTrackShellFocus() at 0x710c0
DispatchEvent() at 0xf7708ee8
DecideToDispatch() at 0xf7709520
XtDispatchEvent() at 0xf77096d8
XtAppMainLoop() at 0xf77099d4
main() at 0x23a4
I may not look at this news group for a week, and our news service only
keeps 3 days worth. So if you think you know a fix, please e-mail it
to me at sxb@dione.cray.com