@Ben wrote:
Yes to a large extent DVR can replace AEs. There is only one issue with DVR's and as long as you knowa about it, you can avoid. WHen using multiple DVR's there is a potential for a dead-lock condition where two threads each have access to a DVR but are dead-locked waiting fo rthe other DVR. The analogous situation using AEs could use one AE inside antoher AE. Since recursion of AEs is difficult (is it impossible?) the dead-locks can be avoided.
So watch out for dead-locks and DVR away!
Just so you know, if you have two processes and two DVRs, as long as each process uses a single Inplace Element Structure to acquire both DVRs, LabVIEW has built in mechanism to avoid the deadlock known as the Dining Philosopher's Problem. The IPE will acquire the DVRs in refnum numerical order every time, thus guaranteeing that if a process gets one of the DVRs, it will get both of the DVRs, and no other process will get any of the DVRs until it can both of the DVRs. Any time you have multiple DVRs shared by the same two processes, and you are going to have the same subroutine using both of them, you should acquire both DVRs using a single IPE.
