if I delete a patch dynamically using "defer_front" in the free message in one of my externals,

can I expect the "fronted" message to be executed first?

Being not sure in what order objects are deleted I'd like this to be the first thing done

Is this reliable or do I have a race condition here?

void prioritized_deref(t_transport_control *x)

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

void transport_control_free(t_transport_control *x)

defer_front(x, (method)prioritized_deref, NULL, 0, NULL);

if I delete a patch dynamically using "defer_front" in the free message in one of my externals,
can I expect the "fronted" message to be executed first?
Being not sure in what order objects are deleted I'd like this to be the first thing done
when the patch gets deleted.

void prioritized_deref(t_transport_control *x)
{
    itm_dereference(x->track_itm);
}
//--------------------------------------------------------------------------------------------------
void transport_control_free(t_transport_control *x)
{
    defer_front(x, (method)prioritized_deref, NULL, 0, NULL);
	freeobject(x->timeobj);
}


defer_front-can-i-rely-on-this-regarding-this-context

in practice using defer_front has the effect that

is called before the referenced transport is deleted.

Calling itm_dereference without defer_front does somehow not work in my case.

If the transport is not dereferenced properly I'm experiencing

artefacts the next time I create a transport with the same name.

About your idea: are you sure the object receives the notification before it's free method is called?

And aren't notifications then send for any action regarding the patcher?

in practice using defer_front has the effect that
itm_dereference(x->track_itm);
is called before the referenced transport is deleted.
Calling itm_dereference without defer_front does somehow not work in my case.

If the transport is not dereferenced properly I'm experiencing
artefacts the next time I create a transport with the same name.

About your idea: are you sure the object receives the notification before it's free method is called?
And aren't notifications then send for any action regarding the patcher?


what you say totally makes sense but somehow makes my patch crash after creating a transport with the same name a second time. (this is the kind of crash I'm experiencing in any case not using defer_front)

I tried calling deref on "willfree" and "free". The notify method worked correctly.

I'll have to stick to deref_front since it turned out to be the only way that works.

what you say totally makes sense but somehow makes my patch crash after creating a transport with the same name a second time. (this is the kind of crash I'm experiencing in any case not using defer_front)
I tried calling deref on "willfree" and "free". The notify method worked correctly.

I'll have to stick to deref_front since it turned out to be the only way that works.
Anyone an idea what's going on?


–––––––––––––––––––––––––

Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000014

--> __PAGEZERO 0000000000000000-0000000000001000 [ 4K] ---/--- SM=NUL /Applications/Max6/Max.app/Contents/MacOS/Max

__TEXT 0000000000001000-0000000000676000 [ 6612K] rwx/rwx SM=COW /Applications/Max6/Max.app/Contents/MacOS/Max

Thread 0:: Dispatch queue: com.apple.main-thread

0 libsystem_kernel.dylib     0x9236e7d2 mach_msg_trap + 10

1 libsystem_kernel.dylib     0x9236dcb0 mach_msg + 68

2 com.apple.CoreFoundation     0x93cf2599 __CFRunLoopServiceMachPort + 185

3 com.apple.CoreFoundation     0x93cf7f7f __CFRunLoopRun + 1247

4 com.apple.CoreFoundation     0x93cf763a CFRunLoopRunSpecific + 378

5 com.apple.CoreFoundation     0x93cf74ab CFRunLoopRunInMode + 123

6 com.apple.HIToolbox     0x92ac815a RunCurrentEventLoopInMode + 242

7 com.apple.HIToolbox     0x92ac7ec9 ReceiveNextEventCommon + 374

8 com.apple.HIToolbox     0x92ac7d44 BlockUntilNextEventMatchingListInMode + 88

9 com.apple.AppKit     0x98b39a3a _DPSNextEvent + 724

10 com.apple.AppKit     0x98b3926c -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 119

11 com.apple.AppKit     0x98b2f6cc -[NSApplication run] + 855

12 com.cycling74.Max     0x0043270f juce::MessageManager::runDispatchLoop() + 731

13 com.cycling74.Max     0x002c1f02 juce::JUCEApplication::main(juce::StringArray const&) + 68

14 com.cycling74.Max     0x002c2025 juce::JUCEApplication::main(int, char const**) + 73

15 com.cycling74.Max     0x0000db8b _start + 209

16 com.cycling74.Max     0x0000dab9 start + 41

Thread 1:: Dispatch queue: com.apple.libdispatch-manager

0 libsystem_kernel.dylib     0x923719ae kevent + 10

1 libdispatch.dylib     0x96507c71 _dispatch_mgr_invoke + 993

2 libdispatch.dylib     0x965077a9 _dispatch_mgr_thread + 53

0 com.cycling74.Max     0x00242bbb itm_permtick + 28

1 com.cycling74.Max     0x000147a7 clock_execute + 54

2 com.cycling74.Max     0x00033ee6 sched_takepoll + 504

3 com.cycling74.Max     0x00033f36 sched_poll + 26

4 com.cycling74.Max     0x00071951 systimer_pollaction + 18

5 com.cycling74.Max     0x00071c62 mactimer_isr + 106

6 com.apple.CoreServices.CarbonCore    0x914250e0 TimerThread + 129

7 libsystem_c.dylib     0x91284557 _pthread_start + 344

8 libsystem_c.dylib     0x9126ecee thread_start + 34

0 libsystem_kernel.dylib     0x923708e2 __psynch_cvwait + 10

1 libsystem_c.dylib     0x91289289 _pthread_cond_wait + 938

2 libsystem_c.dylib     0x91289512 pthread_cond_timedwait_relative_np + 47

3 com.apple.CoreServices.CarbonCore    0x9143f6ad TSWaitOnConditionTimedRelative + 177

4 com.apple.CoreServices.CarbonCore    0x9143f184 TSWaitOnSemaphoreCommon + 272

5 com.apple.CoreServices.CarbonCore    0x9143f40d TSWaitOnSemaphoreRelative + 24

6 com.apple.CoreServices.CarbonCore    0x91424ef1 DeferredTaskThread + 146

2 com.apple.audio.midi.CoreMIDI     0x010ce22d XServerMachPort::ReceiveMessage(int&, void*, int&) + 101

3 com.apple.audio.midi.CoreMIDI     0x010ebae0 MIDIProcess::RunMIDIInThread() + 144

4 com.apple.audio.midi.CoreMIDI     0x010f1c48 MIDIProcess::MIDIInPortThread::Run() + 24

5 com.apple.audio.midi.CoreMIDI     0x010cf805 XThread::RunHelper(void*) + 17

6 com.apple.audio.midi.CoreMIDI     0x010cf2ee CAPThread::Entry(CAPThread*) + 196

0 libsystem_kernel.dylib     0x923710ee __workq_kernreturn + 10

1 libsystem_c.dylib     0x9128704c _pthread_workq_return + 45

2 libsystem_c.dylib     0x91286e19 _pthread_wqthread + 448

3 libsystem_c.dylib     0x9126ecca start_wqthread + 30

0 libsystem_kernel.dylib     0x9236e8e6 mach_wait_until + 10

1 libsystem_c.dylib     0x91315c1c nanosleep + 375

2 libsystem_c.dylib     0x91315a46 usleep + 60

3 com.cycling74.Max     0x000703f5 systhread_sleep + 31

4 com.cycling74.Max     0x0023ed51 pathcache_update_do + 362

5 com.cycling74.Max     0x000704d2 systhread_threadproc + 67

6 libsystem_c.dylib     0x91284557 _pthread_start + 344

7 libsystem_c.dylib     0x9126ecee thread_start + 34

1 libsystem_c.dylib     0x91289220 _pthread_cond_wait + 833

2 libsystem_c.dylib     0x9130f0ec pthread_cond_timedwait$UNIX2003 + 70

3 com.cycling74.Max     0x00448be8 juce::WaitableEventImpl::wait(int) + 168

5 com.cycling74.Max     0x0043b608 juce::WaitableEvent::wait(int) const + 26

6 com.cycling74.Max     0x00455cd1 juce::Thread::wait(int) const + 27

7 com.cycling74.Max     0x0032aef0 juce::InternalTimerThread::run() + 58

8 com.cycling74.Max     0x00455bb2 juce::Thread::threadEntryPoint() + 130

9 com.cycling74.Max     0x0043953e juce::threadEntryProc(void*) + 70

10 libsystem_c.dylib     0x91284557 _pthread_start + 344

11 libsystem_c.dylib     0x9126ecee thread_start + 34

0 libsystem_kernel.dylib     0x9236fe9a __accept + 10

1 com.cycling74.Max     0x0041ef4f juce::StreamingSocket::waitForNextConnection() const + 219

2 com.cycling74.Max     0x0022c571 tcpconnection_listenthread + 36

3 com.cycling74.Max     0x000704d2 systhread_threadproc + 67

4 libsystem_c.dylib     0x91284557 _pthread_start + 344

5 libsystem_c.dylib     0x9126ecee thread_start + 34

Thread 2 crashed with X86 Thread State (32-bit):

eax: 0x00000000 ebx: 0x00070000 ecx: 0x0000010d edx: 0x9128b821

edi: 0x111aabd8 esi: 0x111aa940 ebp: 0xb0288ea8 esp: 0xb0288e50

ss: 0x00000023 efl: 0x00010286 eip: 0x00242bbb cs: 0x0000001b

ds: 0x00000023 es: 0x00000023 fs: 0x00000023 gs: 0x0000000f

crash report
–––––––––––––––––––––––––
Crashed Thread:  2

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000014

VM Regions Near 0x14:
--> __PAGEZERO             0000000000000000-0000000000001000 [    4K] ---/--- SM=NUL  /Applications/Max6/Max.app/Contents/MacOS/Max
    __TEXT                 0000000000001000-0000000000676000 [ 6612K] rwx/rwx SM=COW  /Applications/Max6/Max.app/Contents/MacOS/Max

Thread 0:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib        	0x9236e7d2 mach_msg_trap + 10
1   libsystem_kernel.dylib        	0x9236dcb0 mach_msg + 68
2   com.apple.CoreFoundation      	0x93cf2599 __CFRunLoopServiceMachPort + 185
3   com.apple.CoreFoundation      	0x93cf7f7f __CFRunLoopRun + 1247
4   com.apple.CoreFoundation      	0x93cf763a CFRunLoopRunSpecific + 378
5   com.apple.CoreFoundation      	0x93cf74ab CFRunLoopRunInMode + 123
6   com.apple.HIToolbox           	0x92ac815a RunCurrentEventLoopInMode + 242
7   com.apple.HIToolbox           	0x92ac7ec9 ReceiveNextEventCommon + 374
8   com.apple.HIToolbox           	0x92ac7d44 BlockUntilNextEventMatchingListInMode + 88
9   com.apple.AppKit              	0x98b39a3a _DPSNextEvent + 724
10  com.apple.AppKit              	0x98b3926c -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 119
11  com.apple.AppKit              	0x98b2f6cc -[NSApplication run] + 855
12  com.cycling74.Max             	0x0043270f juce::MessageManager::runDispatchLoop() + 731
13  com.cycling74.Max             	0x002c1f02 juce::JUCEApplication::main(juce::StringArray const&) + 68
14  com.cycling74.Max             	0x002c2025 juce::JUCEApplication::main(int, char const**) + 73
15  com.cycling74.Max             	0x0000db8b _start + 209
16  com.cycling74.Max             	0x0000dab9 start + 41

Thread 1:: Dispatch queue: com.apple.libdispatch-manager
0   libsystem_kernel.dylib        	0x923719ae kevent + 10
1   libdispatch.dylib             	0x96507c71 _dispatch_mgr_invoke + 993
2   libdispatch.dylib             	0x965077a9 _dispatch_mgr_thread + 53

Thread 2 Crashed:
0   com.cycling74.Max             	0x00242bbb itm_permtick + 28
1   com.cycling74.Max             	0x000147a7 clock_execute + 54
2   com.cycling74.Max             	0x00033ee6 sched_takepoll + 504
3   com.cycling74.Max             	0x00033f36 sched_poll + 26
4   com.cycling74.Max             	0x00071951 systimer_pollaction + 18
5   com.cycling74.Max             	0x00071c62 mactimer_isr + 106
6   com.apple.CoreServices.CarbonCore	0x914250e0 TimerThread + 129
7   libsystem_c.dylib             	0x91284557 _pthread_start + 344
8   libsystem_c.dylib             	0x9126ecee thread_start + 34

Thread 3:
0   libsystem_kernel.dylib        	0x923708e2 __psynch_cvwait + 10
1   libsystem_c.dylib             	0x91289289 _pthread_cond_wait + 938
2   libsystem_c.dylib             	0x91289512 pthread_cond_timedwait_relative_np + 47
3   com.apple.CoreServices.CarbonCore	0x9143f6ad TSWaitOnConditionTimedRelative + 177
4   com.apple.CoreServices.CarbonCore	0x9143f184 TSWaitOnSemaphoreCommon + 272
5   com.apple.CoreServices.CarbonCore	0x9143f40d TSWaitOnSemaphoreRelative + 24
6   com.apple.CoreServices.CarbonCore	0x91424ef1 DeferredTaskThread + 146
7   libsystem_c.dylib             	0x91284557 _pthread_start + 344
8   libsystem_c.dylib             	0x9126ecee thread_start + 34

Thread 4:
0   libsystem_kernel.dylib        	0x9236e7d2 mach_msg_trap + 10
1   libsystem_kernel.dylib        	0x9236dcb0 mach_msg + 68
2   com.apple.audio.midi.CoreMIDI 	0x010ce22d XServerMachPort::ReceiveMessage(int&, void*, int&) + 101
3   com.apple.audio.midi.CoreMIDI 	0x010ebae0 MIDIProcess::RunMIDIInThread() + 144
4   com.apple.audio.midi.CoreMIDI 	0x010f1c48 MIDIProcess::MIDIInPortThread::Run() + 24
5   com.apple.audio.midi.CoreMIDI 	0x010cf805 XThread::RunHelper(void*) + 17
6   com.apple.audio.midi.CoreMIDI 	0x010cf2ee CAPThread::Entry(CAPThread*) + 196
7   libsystem_c.dylib             	0x91284557 _pthread_start + 344
8   libsystem_c.dylib             	0x9126ecee thread_start + 34

Thread 5:
0   libsystem_kernel.dylib        	0x923710ee __workq_kernreturn + 10
1   libsystem_c.dylib             	0x9128704c _pthread_workq_return + 45
2   libsystem_c.dylib             	0x91286e19 _pthread_wqthread + 448
3   libsystem_c.dylib             	0x9126ecca start_wqthread + 30

Thread 6:
0   libsystem_kernel.dylib        	0x9236e8e6 mach_wait_until + 10
1   libsystem_c.dylib             	0x91315c1c nanosleep + 375
2   libsystem_c.dylib             	0x91315a46 usleep + 60
3   com.cycling74.Max             	0x000703f5 systhread_sleep + 31
4   com.cycling74.Max             	0x0023ed51 pathcache_update_do + 362
5   com.cycling74.Max             	0x000704d2 systhread_threadproc + 67
6   libsystem_c.dylib             	0x91284557 _pthread_start + 344
7   libsystem_c.dylib             	0x9126ecee thread_start + 34

Thread 7:
0   libsystem_kernel.dylib        	0x923708e2 __psynch_cvwait + 10
1   libsystem_c.dylib             	0x91289220 _pthread_cond_wait + 833
2   libsystem_c.dylib             	0x9130f0ec pthread_cond_timedwait$UNIX2003 + 70
3   com.cycling74.Max             	0x00448be8 juce::WaitableEventImpl::wait(int) + 168
4   ???                           	0x03272440 0 + 52896832
5   com.cycling74.Max             	0x0043b608 juce::WaitableEvent::wait(int) const + 26
6   com.cycling74.Max             	0x00455cd1 juce::Thread::wait(int) const + 27
7   com.cycling74.Max             	0x0032aef0 juce::InternalTimerThread::run() + 58
8   com.cycling74.Max             	0x00455bb2 juce::Thread::threadEntryPoint() + 130
9   com.cycling74.Max             	0x0043953e juce::threadEntryProc(void*) + 70
10  libsystem_c.dylib             	0x91284557 _pthread_start + 344
11  libsystem_c.dylib             	0x9126ecee thread_start + 34

Thread 8:
0   libsystem_kernel.dylib        	0x9236fe9a __accept + 10
1   com.cycling74.Max             	0x0041ef4f juce::StreamingSocket::waitForNextConnection() const + 219
2   com.cycling74.Max             	0x0022c571 tcpconnection_listenthread + 36
3   com.cycling74.Max             	0x000704d2 systhread_threadproc + 67
4   libsystem_c.dylib             	0x91284557 _pthread_start + 344
5   libsystem_c.dylib             	0x9126ecee thread_start + 34

Thread 2 crashed with X86 Thread State (32-bit):
  eax: 0x00000000  ebx: 0x00070000  ecx: 0x0000010d  edx: 0x9128b821
  edi: 0x111aabd8  esi: 0x111aa940  ebp: 0xb0288ea8  esp: 0xb0288e50
   ss: 0x00000023  efl: 0x00010286  eip: 0x00242bbb   cs: 0x0000001b
   ds: 0x00000023   es: 0x00000023   fs: 0x00000023   gs: 0x0000000f
  cr2: 0x00000014
Logical CPU: 0


you should free your clock, then dereference itm (forum coding):

void yourobject_free(t_yourobject *x)
{
    dsp_free(x);
    object_free(x->yourclock);
    if (x->itm) {
        object_detach_byptr(x, x->itm);
        itm_dereference(x->itm);
    }
}


The clock referenced is not created in my ext. I'm referencing a transport.

Calling (object_free(x->yourclock) //ref to transport by scriptname)

and dereferencing after that still makes Max crash.

Maybe not a clean but more safe variant: Max doesn't crash if I don't do any deref at all

(I found a way to get rid of the artifacts if a transport with the same name is created twice.)

The clock referenced is not created in my ext. I'm referencing a transport.
Calling (object_free(x->yourclock) //ref to transport by scriptname)
and dereferencing after that still makes Max crash.

Maybe not a clean but more safe variant: Max doesn't crash if I don't do any deref at all
(I found a way to get rid of the artifacts if a transport with the same name is created twice.)

Ok, cut down it looks like the one attached.

Ok, cut down it looks like the one attached.
(At the moment no itm_deref is used)


defer_front - can I rely on this regarding this context?