Debugging NSNotificationCenter

[Andreas Höschler]

Hello all,

my app crashes under GNUstep. It does not crash under MacOSX. I got the 
following stack trace and am stuck

#0  objc_msg_lookup (receiver=0x908da98, op=0xfe71aef8) at sarray.h:230
#1  0xfe480ee6 in GSFormat (s=0x8046760, format=0x908da98, ap=0x80470d4 
"\230Ú\b\tØe\016\tpíKþðÝsþ", locale=0x0) at GSFormat.m:1856
#2  0xfe4935f8 in -[GSPlaceholderString 
initWithFormat:locale:arguments:] (self=0x80e1a88, _cmd=0xfe741820, 
format=0x86e62e8, locale=0x0,
   argList=0x80470d4 "\230Ú\b\tØe\016\tpíKþðÝsþ") at GSString.m:715
#3  0xfe577f44 in -[NSString initWithFormat:arguments:] (self=0x80e1a88, 
_cmd=0xfe74d1d0, format=0x86e62e8,
   argList=0x80470d4 "\230Ú\b\tØe\016\tpíKþðÝsþ") at NSString.m:1049
#4  0xfe5bc617 in +[NSString(GSCategories) stringWithFormat:arguments:] 
(self=0xfe7416c0, _cmd=0xfe734bb8, format=0x86e62e8,
   argList=0x80470d4 "\230Ú\b\tØe\016\tpíKþðÝsþ") at NSZone.h:281
#5  0xfe52a20a in NSLogv (format=0x86e62e8, args=0x80470d4 
"\230Ú\b\tØe\016\tpíKþðÝsþ") at NSLog.m:345
#6  0xfe529ea7 in NSLog (format=0xfe735918) at NSLog.m:252
#7  0xfe532c47 in -[NSNotificationCenter postNotification:] 
(self=0x80b81a8, _cmd=0xfea79788, notification=0x908da98)
   at NSNotificationCenter.m:1106
#8  0xfe53cd0b in -[NSObject performSelector:withObject:] 
(self=0x80b81a8, _cmd=0xfe73ddd8, aSelector=0xfea79788, anObject=0x908da98)
   at NSObject.m:1788
#9  0xfe56262d in -[GSRunLoopPerformer fire] (self=0x81f3b70, 
_cmd=0xfe73de98) at NSRunLoop.m:104
#10 0xfe56345b in -[NSRunLoop(Private) _checkPerformers:] (self=0x60, 
_cmd=0xfe73df48, context=0x82f1810) at NSRunLoop.m:464
#11 0xfe564659 in -[NSRunLoop acceptInputForMode:beforeDate:] 
(self=0x82e1be0, _cmd=0xfe73df90, mode=0xfe73e020, limit_date=0x82f5e18)
   at NSRunLoop.m:906
#12 0xfe564c79 in -[NSRunLoop runMode:beforeDate:] (self=0x82e1be0, 
_cmd=0xfeee3f78, mode=0xfe73e020, date=0x82ebb38) at NSRunLoop.m:1045
#13 0xfedbb91c in -[GSDisplayServer(EventOps) 
getEventMatchingMask:beforeDate:inMode:dequeue:] (self=0x82d7718, 
_cmd=0xfdb0d720,
   mask=4294967295, limit=0x82ebb38, mode=0xfe73e020, flag=1 '\001') at 
GSDisplayServer.m:877
#14 0xfdab8ae3 in -[XGServer(X11Ops) 
getEventMatchingMask:beforeDate:inMode:dequeue:] (self=0x82d7718, 
_cmd=0xfeea7af8, mask=4294967295,
   limit=0x82ebb38, mode=0xfe73e020, flag=1 '\001') at XGServerEvent.m:1989
#15 0xfec96c17 in -[NSApplication 
nextEventMatchingMask:untilDate:inMode:dequeue:] (self=0x81c5348, 
_cmd=0xfeea7d48, mask=4294967295,

I have inserted the following logs in NSNotificationCenter.m

- (void) postNotification: (NSNotification*)notification
{
  NSLog(@"postNotification...");
  NSLog(@"postNotification %@", notification);
  NSLog(@"postNotification %@ %@", notification, [notification name]);
  if (notification == nil)
   {
     [NSException raise: NSInvalidArgumentException
...

The last log that is printed is "postNotification...". Then the app 
crashes with a segmentation fault. It seems someone is posting a bad 
notification. I have no idea how to track this down any further. Hints 
are greatly appreciated!

Regards,

 Andreas