Look: this is not an issue. IPC::Open3 works fine on Windows. What does not work on Windows is a non-blocking read on file handles and any kind of solution which boils down to 'timeout' or 'can read' with respect to filehandles. The thing you have to do is to create threads to perform blocking reads on filehandles. If this is done in a Tk application you should avoid joining your threads before you quit the main loop unless you want to crash miserably. If you adhere to these precautions you can write a multi threaded process piping Tk application under Windows in a safe way. I have learned the lessons well because I have a quite complicated Tk application which monitors and sends command to heavy external processes. The issue here is with code pages however this I've already resolved in a separate node.