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#19194: Improved cross-references in the fcntl module documentation.

This commit is contained in:
Serhiy Storchaka 2013-10-09 14:20:22 +03:00
parent 7880db6136
commit 926099d5ce
1 changed files with 24 additions and 20 deletions
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44
Doc/library/fcntl.rst
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@ -1,5 +1,5 @@
:mod:`fcntl` --- The :func:`fcntl` and :func:`ioctl` system calls
=================================================================
:mod:`fcntl` --- The ``fcntl`` and ``ioctl`` system calls
=========================================================
.. module:: fcntl
:platform: Unix
@ -17,7 +17,8 @@ interface to the :c:func:`fcntl` and :c:func:`ioctl` Unix routines.
All functions in this module take a file descriptor *fd* as their first
argument. This can be an integer file descriptor, such as returned by
``sys.stdin.fileno()``, or a :class:`io.IOBase` object, such as ``sys.stdin``
itself, which provides a :meth:`fileno` that returns a genuine file descriptor.
itself, which provides a :meth:`~io.IOBase.fileno` that returns a genuine file
descriptor.
.. versionchanged:: 3.3
Operations in this module used to raise a :exc:`IOError` where they now
@ -30,7 +31,8 @@ The module defines the following functions:
.. function:: fcntl(fd, op[, arg])
Perform the requested operation on file descriptor *fd* (file objects providing
a :meth:`fileno` method are accepted as well). The operation is defined by *op*
a :meth:`~io.IOBase.fileno` method are accepted as well). The operation is
defined by *op*
and is operating system dependent. These codes are also found in the
:mod:`fcntl` module. The argument *arg* is optional, and defaults to the integer
value ``0``. When present, it can either be an integer value, or a string.
@ -50,8 +52,8 @@ The module defines the following functions:
.. function:: ioctl(fd, op[, arg[, mutate_flag]])
This function is identical to the :func:`fcntl` function, except that the
argument handling is even more complicated.
This function is identical to the :func:`~fcntl.fcntl` function, except
that the argument handling is even more complicated.
The op parameter is limited to values that can fit in 32-bits.
@ -59,7 +61,8 @@ The module defines the following functions:
integer ``0``), an object supporting the read-only buffer interface (most likely
a plain Python string) or an object supporting the read-write buffer interface.
In all but the last case, behaviour is as for the :func:`fcntl` function.
In all but the last case, behaviour is as for the :func:`~fcntl.fcntl`
function.
If a mutable buffer is passed, then the behaviour is determined by the value of
the *mutate_flag* parameter.
@ -94,16 +97,16 @@ The module defines the following functions:
.. function:: flock(fd, op)
Perform the lock operation *op* on file descriptor *fd* (file objects providing
a :meth:`fileno` method are accepted as well). See the Unix manual
a :meth:`~io.IOBase.fileno` method are accepted as well). See the Unix manual
:manpage:`flock(2)` for details. (On some systems, this function is emulated
using :c:func:`fcntl`.)
.. function:: lockf(fd, operation, [length, [start, [whence]]])
This is essentially a wrapper around the :func:`fcntl` locking calls. *fd* is
the file descriptor of the file to lock or unlock, and *operation* is one of the
following values:
This is essentially a wrapper around the :func:`~fcntl.fcntl` locking calls.
*fd* is the file descriptor of the file to lock or unlock, and *operation*
is one of the following values:
* :const:`LOCK_UN` -- unlock
* :const:`LOCK_SH` -- acquire a shared lock
@ -118,13 +121,13 @@ The module defines the following functions:
systems, :const:`LOCK_EX` can only be used if the file descriptor refers to a
file opened for writing.
*length* is the number of bytes to lock, *start* is the byte offset at which the
lock starts, relative to *whence*, and *whence* is as with :func:`fileobj.seek`,
specifically:
*length* is the number of bytes to lock, *start* is the byte offset at
which the lock starts, relative to *whence*, and *whence* is as with
:func:`io.IOBase.seek`, specifically:
* :const:`0` -- relative to the start of the file (:const:`SEEK_SET`)
* :const:`1` -- relative to the current buffer position (:const:`SEEK_CUR`)
* :const:`2` -- relative to the end of the file (:const:`SEEK_END`)
* :const:`0` -- relative to the start of the file (:data:`os.SEEK_SET`)
* :const:`1` -- relative to the current buffer position (:data:`os.SEEK_CUR`)
* :const:`2` -- relative to the end of the file (:data:`os.SEEK_END`)
The default for *start* is 0, which means to start at the beginning of the file.
The default for *length* is 0 which means to lock to the end of the file. The
@ -149,7 +152,8 @@ lay-out for the *lockdata* variable is system dependent --- therefore using the
.. seealso::
Module :mod:`os`
If the locking flags :const:`O_SHLOCK` and :const:`O_EXLOCK` are present
in the :mod:`os` module (on BSD only), the :func:`os.open` function
provides an alternative to the :func:`lockf` and :func:`flock` functions.
If the locking flags :data:`~os.O_SHLOCK` and :data:`~os.O_EXLOCK` are
present in the :mod:`os` module (on BSD only), the :func:`os.open`
function provides an alternative to the :func:`lockf` and :func:`flock`
functions.