CNiTimer and threads?

[Souldog]

If I derive a class from CNiTimer to handle the OnEvent method then the documentaion says this will run in a system thread. My question is: If I derive say 8 classes from CNiTimer will these run in 8 seperate system threads. I don't see these threads in the Task manager.

[drohacek]

There is only 1 timer thread per process. CNiTimer uses the Windows multimedia timer, which is limited to a single instance per process. See
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/multimed/mmtime_4msz.asp

for more information on Windows multimedia timers.

[Souldog]

Thanks for the answer, but that is just not true.
On Win9X there are 32 multimedia timers for the entire system and I can't find any limitation on per-process use. On WinNT each process can have up to 16 multimedia timers. I don't know the specs for W2K and above, but I would use a queue timer.

As I suspected this is a limitation of the NI timer, so I wont use it.

Thanks

[drohacek]

I stand corrected. I had misinterpretted some internal documentation.

You are correct that 1 timer thread per process is an implementation limitation of the CNiTimer class.

David Rohacek
National Instruments

[Souldog]

Thanks for the help