I successfully retrieved strings, arrays, and other data through a custom AudioObjectPropertySelector, but I can only get fixed returns. Whenever I modify it to use dynamic data, it results in an error. Below is my code. case kPlugIn_CustomPropertyID: { *((CFStringRef*)outData) = CFSTR("qin@@@123"); *outDataSize = sizeof(CFStringRef); } break; case kPlugIn_ContainDic: { CFMutableDictionaryRef mutableDic1 = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); CFDictionarySetValue(mutableDic1, CFSTR("xingming"), CFSTR("qinmu")); *((CFDictionaryRef*)outData) = mutableDic1; *outDataSize = sizeof(CFPropertyListRef); // *((CFPropertyListRef*)outData) = mutableDic; } break; case kPlugIn_ContainArray: { CFMutableArrayRef mutableArray = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks); CFArrayAppendValue(mutableArray, CFSTR("Hello")); CFArrayAppendValue(mutableArray, CFSTR("World")); *((CFArrayRef*)outData) = mutableArray; *outDataSize = sizeof(CFArrayRef); } break; These are fixed returns, and there are no issues when I retrieve the data. When I change the return data in kPlugIn_ContainDic to the following, the first time I restart the CoreAudio service and retrieve the data, it works fine. However, when I attempt to retrieve it again, it results in an error: case kPlugIn_ContainDic: { *outDataSize = sizeof(CFPropertyListRef); *((CFPropertyListRef*)outData) = mutableDic; } break; error code： HALC_ShellDevice::CreateIOContextDescription: failed to get a description from the server HAL_HardwarePlugIn_ObjectGetPropertyData: no object HALPlugIn::ObjectGetPropertyData: got an error from the plug-in routine, Error: 560947818 (!obj) The declaration and usage of mutableDic are as follows: static CFMutableDictionaryRef mutableDic; static OSStatus BlackHole_Initialize(AudioServerPlugInDriverRef inDriver, AudioServerPlugInHostRef inHost) { OSStatus theAnswer = 0; gPlugIn_Host = inHost; if (mutableDic == NULL){ mutableDic = CFDictionaryCreateMutable(kCFAllocatorDefault, 100, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); } } static OSStatus BlackHole_AddDeviceClient(AudioServerPlugInDriverRef inDriver, AudioObjectID inDeviceObjectID, const AudioServerPlugInClientInfo* inClientInfo) { CFStringRef string = CFStringCreateWithFormat(kCFAllocatorDefault, NULL, CFSTR("%u"), inClientInfo->mClientID); CFMutableDictionaryRef dic = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); CFDictionarySetValue(dic, CFSTR("clientID"), string); CFDictionarySetValue(dic, CFSTR("bundleID"), inClientInfo->mBundleID); CFDictionarySetValue(mutableDic, string, dic); } Can someone tell me why

1, I saw nullAudio custom properties of the static const AudioObjectPropertySelector kPlugIn_CustomPropertyID = 'PCst'; But I don't know how to use this in a project. 2. What is the difference between PlugIn and Device's custom properties? 3. When I try to customize the PropertySelector for deivce. After adding kAudioObjectPropertyCustomPropertyInfoList NullAudio_HasDeviceProperty method to compile again after restarting coreAudio service, found that virtual devices don't show.