I wasn't presenting a solution; I was just demonstating that if the command happens to be a simple UNIX process that hangs, your code does in fact correctly timeout (for me at least). You could take this as a starting point; firstly, does your code timeout for you too if you replace the command with a simple sleep? And if so, what is the diffence in behaviour between your command and the UNIX 'sleep' command that causes one to fail and not the other? Investigating that difference may lead to further clues.