[ python-Bugs-1238747 ] subprocess.Popen fails inside a Windows service

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Bugs item #1238747, was opened at 2005-07-15 09:31
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Category: Python Library
Group: Platform-specific
Status: Open
Resolution: None
Priority: 5
Submitted By: Adam Kerrison (adamk550)
Assigned to: Nobody/Anonymous (nobody)
Summary: subprocess.Popen fails inside a Windows service

Initial Comment:
If you use subprocess.Popen() from within a Windows service and 
you try to redirect stdout or stderr, the call will fail with a TypeError.

The issue appears to be that if you attempt to redirect stdout and/or 
stderr, the module also needs to set up stdin. Since you haven't 
specified what to do with stdin, the code simple duplicates the 
processes stdin handle using GetStdHandle(STD_INPUT_HANDLE)

However, a Windows service doesn't have stdin etc so the returned 
handle is None. This handle is then passed to DuplicateHandle() 
which fails with the TypeError.

A workaround is to explictly PIPE stdin but I have found at least one 
Windows program (the RCMD.EXE utility) that fails if its stdin is a 
pipe! (RCMD says "Internal Error 109" ...)

The only other workaround is a to explictly open the NUL device and 
use that for stdin.



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You can respond by visiting: 
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