are the VISA functions threadsafe?

[vix]

I developed an application using 4 different threads for serial communication with 4 virtual COM ports (the same reentrant VI is called in every thread).
I discovered that if my applications hangs for some seconds executing one of the VISA functions (before returning with timeout error) I have some problems also in the other threads.

I wasn't able to fiund out if the VISA functions are threadsafe or not.
Could someone give me an answer?

Thanks in advance

[smercurio_fc]

You should read this thread.