os.popen4 and exit codes

[Donn Cave]

Quoth Don Garrett <garrett at bgb.cc>:
|   My understanding for the popen2-4 functions was that they returned the exit
| code as the result of the last related call to close(). This seems to be
| working for me under Windows, but not Linux. This is the inverse of what I
| would expect.

|   The close DOES return the exit code when I use os.popen(), but I need to be
| able to capture stderr.

On UNIX, popen3 is implemented in Python, out of fork and pipe functions,
and unlike popen it returns 100% stock, common file objects.

To get exit status, you have to use the Popen3 class explicitly, so you
can call its wait() function.

	Donn Cave, donn at u.washington.edu