| msg55537 - (view) |
Author: Aki (akineko) |
Date: 2007-08-31 19:14 |
| Hi, I'm not sure this is a right place to write in the problem I found. What I found was: (1) create a thread (2) open a file in the thread (3) everything works fine under Solaris (4) Openning a file in the thread fails intermittenly under Windows Not always it fails. The file is there but it returns: File "h:\prj\socgear\unidbg\tkunidbg\sub.py", line 94, in thread_worker fd = open(fn, 'rb') IOError: [Errno 2] No such file or directory: './XXX.dat' (5) The problem goes away (under Windows) if I have the main thread wait until the file is opened using Event. // The program also uses Tkinter but I'm not sure that is relevant. I cannot submit the whole program as it is too big to submit. Aki- |
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| msg55542 - (view) |
Author: Martin v. Löwis (loewis) *  |
Date: 2007-08-31 22:21 |
| I don't see the problem. When open() reports that the file does not exist, the most likely reason is that it really does not exist. Perhaps it has not been created, yet, and you need to wait until it has been created before you can open it? |
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| msg55543 - (view) |
Author: Aki (akineko) |
Date: 2007-08-31 22:55 |
| I know it is hard to believe. I spent days to try out many things. For example, I added the following: try: print os.path.isfile(fn) <<<--- fd = open(fn, 'rb') crypted = fd.read() fd.close() idx = crypted.index('\n') except (IOError, OSError, ValueError,): raise When I run, I got following cases randomly: (1) True, Open successfully (2) True, Open failed (3) False, Open failed (4) False, Open successfully The file is a binary data file and is already sitting in the directory before the execution of the program. I know that for other people it is very difficult to work on such case. But this is something to do with threading under windows. Aki- |
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| msg55544 - (view) |
Author: Gabriel Genellina (ggenellina) |
Date: 2007-09-01 01:03 |
| Does the file exist before program is started, and remains after program finishes? If it is your program which creates the file, you may have a race condition. Maybe some delays/retries will be enough, or perhaps you will have to use some other syncronization mechanisms. Also, I see you use a relative path. Do you change the current directory (with os.chdir or similar)? |
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| msg55545 - (view) |
Author: Aki (akineko) |
Date: 2007-09-01 01:11 |
| Sorry to disappoint you but ... (1) Does the file exist before program is started, and remains after program finishes? Yes and Yes (2) Do you change the current directory (with os.chdir or similar)? No. The file is in the current directory where the program was invoked. // Probably, only way to settle this is to create a small test case. But I'm not sure if that is easy. (For example, this problem won't occur if no activity in the main thread.) Aki- |
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| msg55550 - (view) |
Author: Martin v. Löwis (loewis) * |
Date: 2007-09-01 05:34 |
| I'm closing this as "works for me" now. It cannot possibly be a bug in Python, since the error was created by the operating system; Python does not make it up randomly. I also doubt that the operating system will arbitrarily report that a file is not present if the calling process uses threads. So if you can come up with a reproducible test case, please submit a new bug report. Otherwise, you are on your own figuring out what's going on. |
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