A question for you Ruby nerds: the $? variable gives access to the exit code for the last process launched by Ruby. Is referencing $? a race condition in a system with many threads launching many subprocesses? If it is truly a global variable, then it's inherently unsafe, but it could also be implemented with a thread-local variable. Any idea which it is?

</p> <pre> output = `#{command}` if $? != 0 # Race condition? raise output end </pre> <p>