QtCore4.dll_unloaded exception when usin external Wait function (LabVIEW)

[dadreamer]

I'm sorry for bumping such an old thread, but I'm facing similar issue.

I work with Ranger E50414 3D Cameras by SICK IVP in LabVIEW and use the vendor-provided toolkit for that. So, from time to time my program, which works with the cameras, crashes on exit with the exception C0000005 (Access violation) for QtCore4.dll_unloaded module. It's somehow related to QtCore4.dll, which, as I know, is used internally in vendor's library icon_c_51.dll. Here's the screenshot of the crash along with the threads' information about which threads are still alive when the program is crashed.

sick_icon_dll_crash.jpg

(Here's more detailed picture).

I should notice that such event happens only when I close already stopped VI and then close LabVIEW or when I close compiled app (exe) completely. So, this happens in both LabVIEW and exe variant. And this happens not every time, but sometimes (especially, when I quickly close my app or when it closes itself by some conditions). I suppose, it's related to thread synchronization in icon_c_51.dll or Qt DLLs, but my skills aren't enough to figure it out.

I'm working in LabVIEW 2016 32-bit on Windows 7 x64 and using the toolkit sick_lib_sick_3d_camera_toolkit_for_labview-3.1.1.38.vip. Here are the versions of the DLLs:
icon_c_51.dll : 5.1.2.49
QtCore4.dll : 4.5.0.0
QtGui4.dll : 4.5.0.0
QtXml4.dll : 4.5.0.0
Tried to switch to 4.7.4.0 Qt lib's but it didn't help. Also tried to use an explicit loading / unloading with LoadLibrary / FreeLibrary to no avail.

I'm familiar with C, asm and debuggers like IDA and ollydbg but I'm not a Qt programmer so don't know which routines I should check. Any ideas are welcome.

Cross-post on NI forums: https://forums.ni.com/t5/LabVIEW/QtC...t/td-p/3695012