Detecting a GUI session

Christian Heimes lists at
Thu Jan 8 02:31:24 CET 2009

Leith Bade schrieb:
> I would like to know whether my GUI program is being run under python or
> pythonw.
> I would like to know this so I can redirect stderr when their is no
> console window (pythonw) otherwise leave it spitting to the console
> window (python).
> This is because I debug using python while the customer release build
> uses pythonw.
> I can see their is sys.executable but a google search turned up various
> discussions on what this actually means (e.g when run under an
> integrated exe file - which we do for our release builds).

You can check the file descriptor number of sys.stderr. If
sys.stderr.fileno() returns -1 or any other value smaller than zero than
stderr is not connected to a stream.


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