Issue457466
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Created on 2001-09-01 01:16 by rcamesz, last changed 2022-04-10 16:04 by admin. This issue is now closed.
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msg6305 - (view) | Author: Robert Amesz (rcamesz) | Date: 2001-09-01 01:16 | |
[Platform: Windows 98, using Python 2.1.1] Simple example: Python 2.1.1 (#20, Jul 20 2001, 01:19:29) [MSC 32 bit (Intel)] on win32 Type "copyright", "credits" or "license" for more information. >>> import os >>> w,r = os.popen2('dir "C:\\Program Files\\*.*"') I have found that under certain conditions popenx() (x = 2,3,4) will go to never-never land after issuing a warning beep (Windows "attention sign"). I eventually tracked this down as being caused by the fact that the commandline sometimes gets broken down into several parts when double quotes and spaces are present in a certain way in popen's commandline parameter. This prompts w9xpopen.exe to present an invisibe(!) warning mesagebox to the user, assuming it was invoked manually. Being invisible means you can't click the OK-button, and Python grinds to a halt without further warning. To get control back to the Python interpreter you have to press return immediately *without* changing focus. If you do change focus, hitting CTRL-BREAK may be your only option. Sometimes, the task will seemingly end, but actually won't. The CTRL-ALT-DEL tasklist will show a 'W9xpopen' and 'Winoldapp' process active. I am not sure if this bug can actually be fixed all that easily (I've read about similar problems for spawnv()) but there are two things that can be done: 1 - Work around it. I've found that it's possible to escape the double quotes in the usual way (\") and that works fine. For some strange reason it is also neccesary to escape _trailing_ backslashes to \\, or else they are changed into a double quote. Very strange... (Don't forget to *double* those backslashes in ordinary Python strings. I know, four of them at the and of a string does look rather ugly.) Come to think of it, a bugfix within Python's nt-module might use a similar escape-tactic, with some care. 2 - Modify w9xpopen.c slightly, so the error at least doesn't cause the invisible messagebox to pop up. But I've gone a bit further and changed it so it printf's an error message if argc exceeds 2 and then returns. Of course you can't actually *see* that error message, but Python can at least read it from the one of the filehandles which popenx() returns, so it doesn't fail silently. I've attached the modified w9xpopen.c to this bug report. |
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msg6306 - (view) | Author: Tim Peters (tim.peters) * | Date: 2001-09-01 20:11 | |
Logged In: YES user_id=31435 Assigned to MarkH. popen on Win9x is a bottomless pit, and Mark is more familiar with its depths than I am. |
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msg6307 - (view) | Author: Mark Hammond (mhammond) * | Date: 2002-04-03 01:52 | |
Logged In: YES user_id=14198 Fixed. w9xpopen.exe should never display a message box, and argument passing has been fixed so quoted args now work correctly. Lib/test/test_popen.py added. Checking in PC/w9xpopen.c; /cvsroot/python/python/dist/src/PC/w9xpopen.c,v <-- w9xpopen.c new revision: 1.3; previous revision: 1.2 Checking in Modules/posixmodule.c; /cvsroot/python/python/dist/src/Modules/posixmodule.c,v <-- posixmodule.c new revision: 2.227; previous revision: 2.226 Checking in Lib/test/test_popen.py; /cvsroot/python/python/dist/src/Lib/test/test_popen.py,v <- - test_popen.py initial revision: 1.1 Checking in Lib/test/output/test_popen; /cvsroot/python/python/dist/src/Lib/test/output/test_popen,v <-- test_popen initial revision: 1.1 done |
History | |||
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Date | User | Action | Args |
2022-04-10 16:04:24 | admin | set | github: 35088 |
2001-09-01 01:16:40 | rcamesz | create |