How do I keep a GUI alive during a long-running subprocess?

Legacy Wiki Page

This page was migrated from the old MoinMoin-based wiki. Information may be outdated or no longer applicable. For current documentation, see python.org.

This frequently-asked question appears, for example, in this Usenet posting. No single answer is canonical, for each has definite liabilities and limitations; there are, however, a number of expedients which apply in at least some situations:

  • “fire and forget”, that is, put the subprocess in the background and let it run freely;

  • put the subprocess in the background, return to the GUI’s event loop, and poll to detect when the subprocess has terminated;

  • put the subprocess in its own thread, and rely on Python ThreadProgramming …;

  • launch subprocess.Popen() in a conventional way, but interleave attention in a single thread of control between the GUI controller and the stdout from the subprocess.

  • the particular GUI framework involved–wxPython, TkInter, probably has specific mechanisms for managing concurrency in an event-based way. The toolkit behind Tkinter, in fact, already has a Wiki page on the subject above, many of whose hints can be adapted to other frameworks;

  • …

[links, explanations, warnings]