I have several processes running concurrently that I want to log to the same file.
We have been using Enterprise Library 4.1 Logging Application Block (with a Roll
Sorry to say but the answer is no. The File TraceListeners lock the output file so only one TraceListener can log to a file.
You can try other Trace Listeners that are not file based (e.g. Database, Event Log).
Another option I can think of would be to write your own logging service (out of process) that would log to the file and accepts LogEntries. Then create a custom trace listener that sends a message to your service.
It might not be a good idea since you would have a bit of custom development plus it could impact performance since it is an out of process call. Basically you are setting up your own simplified-pseudo-distributor-service.