as I understand it the surrounding TCL code is irrelevant, as is whether the fork is the result of calling [exec], [open "|whatever"] or anything else... the problem is TCL
doesn't/didn't implement pthread_atfork, so threads might lock up any time a new process is fork()/exec()'d by TCL... I understand what you're talking about with running the event loop to avoid blocking, but we don't have any problem with long-running children blocking IO for other threads so it's not related to the problem I thought I might be facing... looks interesting though...
