Popen4 -> null lines on Windows

vincent wehren vincent at visualtrans.de
Tue Dec 30 07:43:22 CET 2003

"Patrick L. Nolan" <pln at cosmic.stanford.edu> schrieb im Newsbeitrag
news:bsqil0$l3i$1 at news.Stanford.EDU...
| We have an application that works on Linux.  It has to be ported
| to Windows XP, and there's one bug that's driving me crazy.
| There's a number-crunching program written in C++.  It is invoked
| by a Tkinter python script.  The script uses the threading
| module to separate out the heavy processing.  The worker thread
| uses popen4 to run the C++ program and capture its standard
| output.  This output is sent to the master thread through a
| queue and displayed by the gui.
| As I said, it works on Linux.  On XP, every call to readline()
| on the program's stdout returns only a zero-length string.
| We are confident that the C++ program doesn't behave that
| way.  We have tried both popen2.popen4 and win32pipe.popen4.
| Does this sound familiar to anyone?

The output doesn't contain any low values by any chance? Does this also
happen when the "mode" flag is set to "b" for binary?

Vincent Wehren

| -- 
| *   Patrick L. Nolan                                          *
| *   W. W. Hansen Experimental Physics Laboratory (HEPL)       *
| *   Stanford University                                       *

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