WMI (winspool) and critical section

[alogrep 0]

HI.

Is accessing  WMI thread safe?

I mean this:

I my Thread repeatedly list the print jobs in the sn spool with  this code

 

 FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
    FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', WbemUser, WbemPassword);
    FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_PrintJob','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
    etc. ......

Do I need to protect that with a criticalsection Acquire/Release?

Thank you

[PeaShooter_OMO 11]

I have used WMI in multiple simultaneous threads before but always created and kept the WMI Objects local to each thread.

 

Are you sure there is no other API/way to do what you want? WMI generally is slow.

Edited May 4, 2023 by PeaShooter_OMO

[alogrep 0]

Yes, there other ways, but they do not work

Anyway, in EACH thread I have a funtcion that  does this

FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
    FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', WbemUser, WbemPassword);
    FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_PrintJob','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
    etc. ......

My question is: do i need to encapsulatwe it in a critical section Acquire/Release?. ( I am rather new to threads, but I would think it is not necessary)

[programmerdelphi2k 237]

@alogrep

see that  

https://social.msdn.microsoft.com/Forums/vstudio/en-US/18866f7c-a896-4465-9208-c920cf1f1158/is-wmi-api-threadsafe-?forum=netfxbcl#:~:text=Your application will be thread,accessing them in different threads.

https://microsoft.public.win32.programmer.wmi.narkive.com/vLmbKJcS/wmi-and-multi-threading

Edited May 4, 2023 by programmerdelphi2k

[alogrep 0]

Thanks.

It seems then I do not need to use a critical section because each thread instantiate the object and use the service.