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Issue #21813: Enhance documentation of the os.stat_result class.

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Victor Stinner 2014-07-24 12:42:16 +02:00
parent a3c80ce8b7
commit 6d4f4feca2
1 changed files with 180 additions and 71 deletions
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Doc/library/os.rst
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@ -765,8 +765,14 @@ as internal buffering of data.
.. function:: fstat(fd)
Return status for file descriptor *fd*, like :func:`~os.stat`. As of Python
3.3, this is equivalent to ``os.stat(fd)``.
Get the status of the file descriptor *fd*. Return a :class:`stat_result`
object.
As of Python 3.3, this is equivalent to ``os.stat(fd)``.
.. seealso::
The :func:`stat` function.
Availability: Unix, Windows.
@ -1570,17 +1576,25 @@ features:
Added support for specifying an open file descriptor for *path*.
.. function:: lstat(path, *, dir_fd=None)
.. function:: lstat(path, \*, dir_fd=None)
Perform the equivalent of an :c:func:`lstat` system call on the given path.
Similar to :func:`~os.stat`, but does not follow symbolic links. On
platforms that do not support symbolic links, this is an alias for
:func:`~os.stat`. As of Python 3.3, this is equivalent to ``os.stat(path,
dir_fd=dir_fd, follow_symlinks=False)``.
Similar to :func:`~os.stat`, but does not follow symbolic links. Return a
:class:`stat_result` object.
On platforms that do not support symbolic links, this is an alias for
:func:`~os.stat`.
As of Python 3.3, this is equivalent to ``os.stat(path, dir_fd=dir_fd,
follow_symlinks=False)``.
This function can also support :ref:`paths relative to directory descriptors
<dir_fd>`.
.. seealso::
The :func:`stat` function.
.. versionchanged:: 3.2
Added support for Windows 6.0 (Vista) symbolic links.
@ -1847,49 +1861,116 @@ features:
The *dir_fd* parameter.
.. function:: stat(path, *, dir_fd=None, follow_symlinks=True)
.. function:: stat(path, \*, dir_fd=None, follow_symlinks=True)
Perform the equivalent of a :c:func:`stat` system call on the given path.
*path* may be specified as either a string or as an open file descriptor.
(This function normally follows symlinks; to stat a symlink add the argument
``follow_symlinks=False``, or use :func:`lstat`.)
Get the status of a file or a file descriptor. Perform the equivalent of a
:c:func:`stat` system call on the given path. *path* may be specified as
either a string or as an open file descriptor. Return a :class:`stat_result`
object.
The return value is an object whose attributes correspond roughly
to the members of the :c:type:`stat` structure, namely:
This function normally follows symlinks; to stat a symlink add the argument
``follow_symlinks=False``, or use :func:`lstat`.
* :attr:`st_mode` - protection bits,
* :attr:`st_ino` - inode number,
* :attr:`st_dev` - device,
* :attr:`st_nlink` - number of hard links,
* :attr:`st_uid` - user id of owner,
* :attr:`st_gid` - group id of owner,
* :attr:`st_size` - size of file, in bytes,
* :attr:`st_atime` - time of most recent access expressed in seconds,
* :attr:`st_mtime` - time of most recent content modification
expressed in seconds,
* :attr:`st_ctime` - platform dependent; time of most recent metadata
change on Unix, or the time of creation on Windows, expressed in seconds
* :attr:`st_atime_ns` - time of most recent access
expressed in nanoseconds as an integer,
* :attr:`st_mtime_ns` - time of most recent content modification
expressed in nanoseconds as an integer,
* :attr:`st_ctime_ns` - platform dependent; time of most recent metadata
change on Unix, or the time of creation on Windows,
expressed in nanoseconds as an integer
This function can support :ref:`specifying a file descriptor <path_fd>` and
:ref:`not following symlinks <follow_symlinks>`.
On some Unix systems (such as Linux), the following attributes may also be
available:
.. index:: module: stat
* :attr:`st_blocks` - number of 512-byte blocks allocated for file
* :attr:`st_blksize` - filesystem blocksize for efficient file system I/O
* :attr:`st_rdev` - type of device if an inode device
* :attr:`st_flags` - user defined flags for file
Example::
On other Unix systems (such as FreeBSD), the following attributes may be
available (but may be only filled out if root tries to use them):
>>> import os
>>> statinfo = os.stat('somefile.txt')
>>> statinfo
os.stat_result(st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027)
>>> statinfo.st_size
264
* :attr:`st_gen` - file generation number
* :attr:`st_birthtime` - time of file creation
Availability: Unix, Windows.
.. seealso::
:func:`fstat` and :func:`lstat` functions.
.. versionadded:: 3.3
Added the *dir_fd* and *follow_symlinks* arguments, specifying a file
descriptor instead of a path.
.. class:: stat_result
Object whose attributes correspond roughly to the members of the
:c:type:`stat` structure. It is used for the result of :func:`os.stat`,
:func:`os.fstat` and :func:`os.lstat`.
Attributes:
.. attribute:: st_mode
File mode: file type and file mode bits (permissions).
.. attribute:: st_ino
Inode number.
.. attribute:: st_dev
Identifier of the device on which this file resides.
.. attribute:: st_nlink
Number of hard links.
.. attribute:: st_uid
User identifier of the file owner.
.. attribute:: st_gid
Group identifier of the file owner.
.. attribute:: st_size
Size of the file in bytes, if it is a regular file or a symbolic link.
The size of a symbolic link is the length of the pathname it contains,
without a terminating null byte.
Timestamps:
.. attribute:: st_atime
Time of most recent access expressed in seconds.
.. attribute:: st_mtime
Time of most recent content modification expressed in seconds.
.. attribute:: st_ctime
Platform dependent:
* the time of most recent metadata change on Unix,
* the time of creation on Windows, expressed in seconds.
.. attribute:: st_atime_ns
Time of most recent access expressed in nanoseconds as an integer.
.. attribute:: st_mtime_ns
Time of most recent content modification expressed in nanoseconds as an
integer.
.. attribute:: st_ctime_ns
Platform dependent:
* the time of most recent metadata change on Unix,
* the time of creation on Windows, expressed in nanoseconds as an
integer.
See also the :func:`stat_float_times` function.
.. note::
@ -1899,6 +1980,7 @@ features:
or FAT32 file systems, :attr:`st_mtime` has 2-second resolution, and
:attr:`st_atime` has only 1-day resolution. See your operating system
documentation for details.
Similarly, although :attr:`st_atime_ns`, :attr:`st_mtime_ns`,
and :attr:`st_ctime_ns` are always expressed in nanoseconds, many
systems do not provide nanosecond precision. On systems that do
@ -1908,41 +1990,68 @@ features:
If you need the exact timestamps you should always use
:attr:`st_atime_ns`, :attr:`st_mtime_ns`, and :attr:`st_ctime_ns`.
For backward compatibility, the return value of :func:`~os.stat` is also
On some Unix systems (such as Linux), the following attributes may also be
available:
.. attribute:: st_blocks
Number of 512-byte blocks allocated for file.
This may be smaller than :attr:`st_size`/512 when the file has holes.
.. attribute:: st_blksize
"Preferred" blocksize for efficient file system I/O. Writing to a file in
smaller chunks may cause an inefficient read-modify-rewrite.
.. attribute:: st_rdev
Type of device if an inode device.
.. attribute:: st_flags
User defined flags for file.
On other Unix systems (such as FreeBSD), the following attributes may be
available (but may be only filled out if root tries to use them):
.. attribute:: st_gen
File generation number.
.. attribute:: st_birthtime
Time of file creation.
On Mac OS systems, the following attributes may also be available:
.. attribute:: st_rsize
Real size of the file.
.. attribute:: st_creator
Creator of the file.
.. attribute:: st_type
File type.
The standard module :mod:`stat` defines functions and constants that are
useful for extracting information from a :c:type:`stat` structure. (On
Windows, some items are filled with dummy values.)
For backward compatibility, a :class:`stat_result` instance is also
accessible as a tuple of at least 10 integers giving the most important (and
portable) members of the :c:type:`stat` structure, in the order
:attr:`st_mode`, :attr:`st_ino`, :attr:`st_dev`, :attr:`st_nlink`,
:attr:`st_uid`, :attr:`st_gid`, :attr:`st_size`, :attr:`st_atime`,
:attr:`st_mtime`, :attr:`st_ctime`. More items may be added at the end by
some implementations.
This function can support :ref:`specifying a file descriptor <path_fd>` and
:ref:`not following symlinks <follow_symlinks>`.
.. index:: module: stat
The standard module :mod:`stat` defines functions and constants that are useful
for extracting information from a :c:type:`stat` structure. (On Windows, some
items are filled with dummy values.)
Example::
>>> import os
>>> statinfo = os.stat('somefile.txt')
>>> statinfo
posix.stat_result(st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027)
>>> statinfo.st_size
264
Availability: Unix, Windows.
some implementations. For compatibility with older Python versions,
accessing :class:`stat_result` as a tuple always returns integers.
.. versionadded:: 3.3
Added the *dir_fd* and *follow_symlinks* arguments,
specifying a file descriptor instead of a path,
and the :attr:`st_atime_ns`, :attr:`st_mtime_ns`,
and :attr:`st_ctime_ns` members.
Added the :attr:`st_atime_ns`, :attr:`st_mtime_ns`, and
:attr:`st_ctime_ns` members.
.. function:: stat_float_times([newvalue])