Re: edm troubles

[John Sinclair <sinclairjw@ornl.gov>]

Pierre,

There is a problem with the Xt lib version distributed with RHEL5. 
Someone suggested that the latest
version may be fixed but I'm not entirely sure about this. At the least, 
make sure you do have the latest
version of X and Xt lib. Motif is not a problem.

I have enclosed a test program that may demonstrate the problem. To 
build, place 1.c and makefile
in a directory, cd into that directory, and type "make". This will build 
the executable file named 1.
To run type "./1". The program launches a window with a menu bar to open 
additional windows.
These additional windows contain a menu bar with an "exit" entry to 
close the window. In my
experience, opening several of these windows (sometimes a few, sometimes 
20-30) and then closing
them eventually causes the same crash (at least the crash dump looks the 
same).

This crash has an interesting history. As you may know, the XFree86 
development was taken over
by X.org because of a license issue in a particular version of XFree86. 
This same bug existed in a
past version of the XFree86 distribution. Fortunately, it was fixed 
promptly. When I look at the crash dump,
I strongly suspect the X.org development is following along the same 
path and has duplicated this bug.

I am sending a copy of this reply to tech-talk in case anyone has solved 
this problem.

John Sinclair

mattei pierre wrote:
> Hello John,
> I am switching from MEDM to EDM for a new application and I have some 
> troubles during execution. EDM have sometimes crashes with one of 
> these messages :
> -segmentation error  (most frequently)
> -xtErrorHandler - Object "(null)" does not have windowed ancestor
> -xtErrorHandler - Cannot find callback list in XtCallCallbacks
>  Too many Xt errors
> -xtErrorHandler - XtRemoveGrab asked to remove a widget not on the list
> -xtErrorHandler - Cannot find callback list in XtCallCallbacks
>  Too many Xt error
>
> I think I follow all instructions during the installation.
> I uses RHEL5, EPICS base-3.14.9, openmotif, X11 etc...
>
> Have you any ideas of something I have done wrong ?
>
> Best regards,

/* ---------------------------------------------
 *
 * This application creates a main window and raises it
 * approximately every 3 seconds. The only menu option
 * is "exit".
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <math.h>
#include <sys/types.h>
#include <sys/time.h>
#include <time.h>
#include <wait.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>

#include <X11/Xlib.h>
#include <X11/Intrinsic.h>
#include <Xm/Xm.h>
#include <Xm/AtomMgr.h>
#include <Xm/Protocols.h>
#include <Xm/MainW.h>
#include <Xm/PushB.h>
#include <Xm/CascadeB.h>
#include <Xm/RowColumn.h>

static int g_exit = 0;
XtAppContext app;
Display *display;
Widget widgetToKill = NULL;

void exit_cb (
  Widget w,
  XtPointer client,
  XtPointer call )
{

int *flag = (int *) client;

  printf( "exit_cb callback function was invoked\n" );

  *flag = 1;

}

void exitOne_cb (
  Widget w,
  XtPointer client,
  XtPointer call )
{

  printf( "exitOne_cb callback function was invoked\n" );

  do {
    widgetToKill = w;
    w = XtParent( w );
  } while ( w );

}

void newWin_cb (
  Widget w,
  XtPointer client,
  XtPointer call )
{

Widget appTop1, mainWin1, menuBar1, filePullDown1, fileCascade1, exitB1;
XmString menuStr, str;
Atom wm_delete_window;

  appTop1 = XtVaAppCreateShell( NULL, "test", applicationShellWidgetClass,
   display,
   XmNiconic, False,
   XmNmappedWhenManaged, True,
   NULL );

  mainWin1 = XtVaCreateManagedWidget( "main", xmMainWindowWidgetClass,
   appTop1,
   XmNscrollBarDisplayPolicy, XmAS_NEEDED,
   XmNscrollingPolicy, XmAUTOMATIC,
   NULL );

  menuBar1 = XmCreateMenuBar( mainWin1, "menubar", NULL, 0 );

  filePullDown1 = XmCreatePulldownMenu( menuBar1, "file", NULL, 0 );

  menuStr = XmStringCreateLocalized( "file" );
  fileCascade1 = XtVaCreateManagedWidget( "filemenu", xmCascadeButtonWidgetClass,
   menuBar1,
   XmNlabelString, menuStr,
   XmNmnemonic, 'f',
   XmNsubMenuId, filePullDown1,
   NULL );
  XmStringFree( menuStr );

  str = XmStringCreateLocalized( "exit" );
  exitB1 = XtVaCreateManagedWidget( "pb", xmPushButtonWidgetClass,
   filePullDown1,
   XmNlabelString, str,
   NULL );
  XmStringFree( str );
  XtAddCallback( exitB1, XmNactivateCallback, exitOne_cb,
   (XtPointer) &g_exit );

  XtManageChild( menuBar1 );

  XtRealizeWidget( appTop1 );

  wm_delete_window = XmInternAtom( display, "WM_DELETE_WINDOW", False );
  XmAddWMProtocolCallback( appTop1, wm_delete_window,
   exitOne_cb, (XtPointer) &g_exit );
  XtVaSetValues( appTop1, XmNdeleteResponse, XmDO_NOTHING, NULL );

}

int main (
  int argc,
  char **argv
) {

Widget appTop, mainWin, menuBar, filePullDown, fileCascade, exitB;
XmString menuStr, str;
XEvent Xev;
int result, isXEvent, n, count;
struct timespec req, rem;
Atom wm_delete_window;

  XtToolkitInitialize();
  app = XtCreateApplicationContext();

  display = XtOpenDisplay( app, NULL, NULL, "test", NULL, 0, &argc,
   argv );

  appTop = XtVaAppCreateShell( NULL, "test", applicationShellWidgetClass,
   display,
   XmNiconic, False,
   XmNmappedWhenManaged, True,
   NULL );

  mainWin = XtVaCreateManagedWidget( "main", xmMainWindowWidgetClass,
   appTop,
   XmNscrollBarDisplayPolicy, XmAS_NEEDED,
   XmNscrollingPolicy, XmAUTOMATIC,
   NULL );

  menuBar = XmCreateMenuBar( mainWin, "menubar", NULL, 0 );

  filePullDown = XmCreatePulldownMenu( menuBar, "file", NULL, 0 );

  menuStr = XmStringCreateLocalized( "file" );
  fileCascade = XtVaCreateManagedWidget( "filemenu", xmCascadeButtonWidgetClass,
   menuBar,
   XmNlabelString, menuStr,
   XmNmnemonic, 'f',
   XmNsubMenuId, filePullDown,
   NULL );
  XmStringFree( menuStr );

  str = XmStringCreateLocalized( "new" );
  exitB = XtVaCreateManagedWidget( "pb", xmPushButtonWidgetClass,
   filePullDown,
   XmNlabelString, str,
   NULL );
  XmStringFree( str );
  XtAddCallback( exitB, XmNactivateCallback, newWin_cb,
   (XtPointer) &g_exit );

  XtManageChild( menuBar );

  XtRealizeWidget( appTop );

  wm_delete_window = XmInternAtom( display, "WM_DELETE_WINDOW", False );
  XmAddWMProtocolCallback( appTop, wm_delete_window,
   exit_cb, (XtPointer) &g_exit );
  XtVaSetValues( appTop, XmNdeleteResponse, XmDO_NOTHING, NULL );

  //-------------------------------------------

  n = 0;

  while ( !g_exit ) {

    count = 1000;

    do {
      result = XtAppPending( app );
      if ( result ) {
        isXEvent = XtAppPeekEvent( app, &Xev );
        if ( isXEvent ) {
          if ( Xev.type != Expose ) {
            XtAppProcessEvent( app, result );
          }
          else {
            XtAppProcessEvent( app, result );
          }
        }
        else { // process all timer or alternate events
          XtAppProcessEvent( app, result );
        }
      }
      count--;
    } while ( result && count );

    req.tv_sec = 0;
    req.tv_nsec = 100000000;
    nanosleep( &req, &rem );

    // raise window approx every 3 seconds
    n++;
    if ( n == 30 ) {
      n = 0;
      printf( "call XRaiseWindow\n" );
      XRaiseWindow( display, XtWindow(appTop) );
    }

    if ( widgetToKill ) {
      XtDestroyWidget( widgetToKill );
      widgetToKill = NULL;
    }

  }

  return 0;

}

CFLAGS = -Wall -O0 -g
LDFLAGS = -g

all : 1

1 : 1.o
	g++ $(LDFLAGS) -o 1 \
	-L/usr/X11R6/lib \
	-lXm -lXt -lX11 \
	1.o

1.o : 1.c
	cc $(CFLAGS) -o 1.o -c 1.c