I don't think I understand how to do that in my case. I am in the middle of a large program and need to make some sub calls to some XS/external lib subs. There isn't anything I can really launch as an external processs here. Am I missing something? I know it'll always work if I redirect everything before I start but my problem is that I am already deep in some code at the point where I need to run some XS subs and get their STDERR.