You nailed it, Kevin. Thanks so much!
It is due to the static C++ wrapper object.
After I moved it to the heap, the crash was fixed.
Thanks,
Beinan
On Thu, Oct 23, 2014 at 12:50 PM, Kevin Meaney <k...@yvs.eu.com> wrote:
> Personally I'd try and not call any objective-c code from a C++ static
> object. If it did look the appropriate solution then I'd make sure I was
> comfortable with my knowledge of the objective-c runtime and the order in
> which things are called before main is called.
>
> Kevin
>
> On 23 Oct 2014, at 13:02, Beinan Li <li.bei...@gmail.com> wrote:
>
> Thank you Kevin!
> I didn't know this before. This might be it because I did at some point
> change the dictionary creation from the old API-based syntax to literals.
> Maybe I should move back to the API calls. I'll try that today.
>
> Thanks,
> Beinan
>
>
> On Thu, Oct 23, 2014 at 5:18 AM, Kevin Meaney <k...@yvs.eu.com> wrote:
>
>>
>> On 23 Oct 2014, at 00:34, Beinan Li <li.bei...@gmail.com> wrote:
>>
>> Oh! I did actually.
>>
>> The method I posted belongs to an ObjC object which is wrapped by a C++
>> object.
>> That C++ object is a singleton (static).
>>
>> How is this going to affect ARC and why it didn't down-right crash a week
>> ago before I upgraded Xcode?
>>
>>
>> I wouldn't worry about why it worked before. I don't think that helps,
>> and if you have any other cases they should be removed as well.
>>
>> Array and dictionary literals are not evaluated at compile time but are
>> replaced with the objective-c calls to create the arrays and dictionaries.
>> This is very different to string literals.
>>
>> From what I understand any code that is executed before main is called is
>> done so before the objective-c runtime is fully setup which means you have
>> no guarantees about what will work. In objective-c++ where you can create
>> static C++ objects that results in objective-c being called it is an easy
>> way to make difficult to track crashes.
>>
>> I'd like confirmation from an apple engineer that my understanding is
>> correct. My quick perusal of the docs didn't find the info I was after.
>>
>> Kevin
>>
>> Thanks,
>> Beinan
>>
>>
>> On Wed, Oct 22, 2014 at 7:00 PM, Kevin Meaney <k...@yvs.eu.com> wrote:
>>
>>> Your not creating a static C++ object anywhere are you? One that creates
>>> the dictionary before main gets called by any chance?
>>>
>>> Kevin
>>>
>>> Sent from my iPhone
>>>
>>> > On 22 Oct 2014, at 22:45, Beinan Li <li.bei...@gmail.com> wrote:
>>> >
>>> > Note, the initial crashing function is merely translating a C++ enum
>>> to the
>>> > AVFoundation builtin constants.
>>> >
>>> > Thanks,
>>> > Beinan
>>> >
>>> >
>>> >> On Wed, Oct 22, 2014 at 5:45 PM, Beinan Li <li.bei...@gmail.com>
>>> wrote:
>>> >>
>>> >> It is quite unpredictable.
>>> >> At first it crashes at a dictionary creation line in a .mm
>>> implementation
>>> >> like this:
>>> >>
>>> >> - (NSString*) getAVAudioSessionMode:(myAudioSessionMode)modeKey {
>>> >> NSDictionary* modeDict = @{ // Here it crashes
>>> >> @(myAudioSessionModeDefault): AVAudioSessionModeDefault,
>>> >> @(myAudioSessionModeVoiceChat): AVAudioSessionModeVoiceChat,
>>> >> @(myAudioSessionModeGameChat): AVAudioSessionModeGameChat,
>>> >> @(myAudioSessionModeVideoRecording):
>>> AVAudioSessionModeVideoRecording,
>>> >> @(myAudioSessionModeMeasurement): AVAudioSessionModeMeasurement,
>>> >> @(myAudioSessionModeMoviePlayback): AVAudioSessionModeMoviePlayback,
>>> >> @(myAudioSessionModeVideoChat): AVAudioSessionModeVideoChat
>>> >> };
>>> >> NSString* mode = [modeDict objectForKey:@
>>> >> (mySettings.audioSession.eMode)];
>>> >> return mode;
>>> >> }
>>> >>
>>> >> The backtrace gives me:
>>> >>
>>> >> * thread #1: tid = 0x2403, 0x0013148c MyDemo`-[MyImp
>>> >> getAVAudioSessionMode:](self=0x1e839a80, _cmd=0x002d3077,
>>> >> modeKey=myAudioSessionModeDefault) + 676 at MyImp.mm:78, queue =
>>> >> 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1,
>>> address=0x0)
>>> >> * frame #0:
>>> >> 0x0013148c MyDemo -[MyImp getAVAudioSessionMode:](self=0x1e839a80,
>>> >> _cmd=0x002d3077, modeKey=myAudioSessionModeDefault) + 676 at
>>> MyImp.mm:78
>>> >>
>>> >> Then if I remove this dictionary all together and do it like this:
>>> >>
>>> >> - (NSString*) getAVAudioSessionMode:(myAudioSessionMode)modeKey {
>>> >> return AVAudioSessionModeDefault;
>>> >> }
>>> >>
>>> >> Then I get a crash right in the main.mm:
>>> >>
>>> >> int retVal = UIApplicationMain(argc, argv, nil, @"MyDemoAppDelegate");
>>> >>
>>> >> backtrace:
>>> >>
>>> >> * thread #1: tid = 0x2403, 0x3c4df350
>>> >> libsystem_kernel.dylib`__pthread_kill + 8, queue =
>>> 'com.apple.main-thread',
>>> >> stop reason = signal SIGABRT
>>> >> frame #0: 0x3c4df350 libsystem_kernel.dylib`__pthread_kill + 8
>>> >> frame #1: 0x3c456122 libsystem_c.dylib`pthread_kill + 58
>>> >> frame #2: 0x3c492972 libsystem_c.dylib`abort + 94
>>> >> frame #3: 0x3ba30d4e libc++abi.dylib`abort_message + 74
>>> >> frame #4: 0x3ba2dff8 libc++abi.dylib`default_terminate() + 24
>>> >> frame #5: 0x3bfe1a
>>>
>>
>>
>>
>
>
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