Hi. I'm rtying to use pipes to communicate between a python GUI and a spawned C++ program. I prefer not to use forking because the app may be run on windows, where forking isn't supported. Roughly what I'm doing is: (r,w) = os.pipe() spawnl(P_WAIT, 'tool.exe', ' ', message, str(w)) close(w) print os.read(r, 1000) In c++ , ... int main(int argc, char** argv) { }