Hi. I'm currently writing a wxRuby program to visualize wireless network (802.11), and is somewhat stuck with IO.popen behavior under Windows. My software is composed of two parts: one for gathering Wi-Fi information through Windows NDIS/WMI API (CLI program written in C), and the other for controlling the former and visualizing collected result using Ruby/wxWindows. Gathered information is passed over IO.popen pipe. The problem is that whenever I try to close this pipe, it never comes back. After some investigation, I found out IO.close on Windows waits forever until invoked process exits. Actually, this is same on UNIX (pclose(2) behavior), but it was not a issue on UNIX as process gets interrupted by EPIPE. So the question is: How can I run forever-looping CLI program interactively on Windows? What I want to do is essentially as follows: # double click event handler # - this must not block as it kills GUI interactiveness def on_mouse_double_click(event) IO.popen(cmd) do |io| while ! io.eof? do # update progress and check for user-requested cancellation if (user_req = update_progress_bar()) == CANCEL break end # stop processing once enough data is collected if got_enough_data(io.gets) break end end end end As I wrote above, this event handler code blocks after it "broke" out of the loop because implicit IO.close never returns. For now, I worked around the problem by modifying invoked command to exit if certain file exists, and updated above code to create such file once break condition is met. But since this workaround requires access to the source, I'd like to know cleaner way to do the same thing, without any kind of kludge. I also tried doing "kill(SIGKILL, io.pid)" before exiting the loop, but it resulted to general unstability of the program as killed process left environment in uncertain state. Other signals (SIGINT, etc) had no effect on Windows. Any ideas? Thanks in advance.
on 2006-04-03 16:35