Martin v. Löwis schreef: >>> Sure - but what does stat then do when passed NUL? >> AFAIK then it doesn't fill in the size and time fields of the structure >> (or sets them to a useless/invalid value). >> >> (See http://msdn2.microsoft.com/en-us/library/14h5k7ff(vs.71).aspx) > > What specifically on that page tells me how the fields get filled > for NUL? If you are referring to the "if path refers to a device..." > sentence:
Yes, I was > how does it determine that NUL is a device? I'm not sure. I suppose it just calls GetFileSize() etc. The docs for GetFileSize() say "You cannot use the GetFileSize function with a handle of a nonseeking device such as a pipe or a communications device. To determine the file type for hFile, use the GetFileType function." GetFileType() on its turn returns one of: FILE_TYPE_UNKNOWN: The type of the specified file is unknown. FILE_TYPE_DISK: The specified file is a disk file. FILE_TYPE_CHAR: The specified file is a character file, typically an LPT device or a console. FILE_TYPE_PIPE: The specified file is either a named or anonymous pipe. But I don't know where it is specified which names refer to devices. I tried to query all device names with QueryDosDevice() (with a very simple C program; I can give you the code though I doubt it's useful), but that returns 208 names (on my system); much more than the LPT1, CON, NUL etc. It also includes stuff like, on my system, "Dritek_KB_Filter", "Sony Ericsson T610 Series Bluetooth (TM) Modem #2" etc. I've tried calling _stat() on those names and it returns -1 meaning "File not found". That behavior is clearly different from CON, NUL etc. I thought I've seen the complete list on MSDN some time before, but I can't find it now. >> See above: if stat() (_stat() actually) is called on NUL (or another >> device), I don't think it does anything useful with these fields. > > You mean, it does nothing documented... AFAICT from the code, it always > fills in something. Yes, it returns 0xffffffff in the time fields and 0 in the size field (at least on my system, Windows XP SP1). I made another small C++ program to see what _stat() does (again, I can give you the code if you want). With a normal file: $ ./stat stat.cpp gid 0 atime 1194169674 = 2007-11-04T10:47:54 ctime 1194167463 = 2007-11-04T10:11:03 dev 2 ino 0 mode 0x81b6 mtime 1194381734 = 2007-11-06T21:42:14 nlink 1 rdev 2 size 1342 uid 0 With a device: $ ./stat NUL gid 0 atime 4294967295 = invalid time ctime 4294967295 = invalid time dev 2 ino 0 mode 0x81b6 mtime 4294967295 = invalid time nlink 1 rdev 2 size 0 uid 0 (The $ and ./ is because I ran the program from an msys shell) (it says "invalid time" because localtime() returns NULL) In summary, I'm afraid all of this doesn't really help very much... -- The saddest aspect of life right now is that science gathers knowledge faster than society gathers wisdom. -- Isaac Asimov Roel Schroeven _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
