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Doc: Update references and examples of old, unsupported OSes and uarches (GH-92791)
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@ -735,9 +735,8 @@ PyConfig
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* ``"utf-8"`` if :c:member:`PyPreConfig.utf8_mode` is non-zero.
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* ``"ascii"`` if Python detects that ``nl_langinfo(CODESET)`` announces
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the ASCII encoding (or Roman8 encoding on HP-UX), whereas the
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``mbstowcs()`` function decodes from a different encoding (usually
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Latin1).
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the ASCII encoding, whereas the ``mbstowcs()`` function
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decodes from a different encoding (usually Latin1).
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* ``"utf-8"`` if ``nl_langinfo(CODESET)`` returns an empty string.
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* Otherwise, use the :term:`locale encoding`:
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``nl_langinfo(CODESET)`` result.
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@ -483,8 +483,14 @@ including :func:`~shutil.copyfile`, :func:`~shutil.copytree`, and
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How do I copy a file?
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---------------------
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The :mod:`shutil` module contains a :func:`~shutil.copyfile` function. Note
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that on MacOS 9 it doesn't copy the resource fork and Finder info.
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The :mod:`shutil` module contains a :func:`~shutil.copyfile` function.
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Note that on Windows NTFS volumes, it does not copy
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`alternate data streams
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<https://en.wikipedia.org/wiki/NTFS#Alternate_data_stream_(ADS)>`_
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nor `resource forks <https://en.wikipedia.org/wiki/Resource_fork>`__
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on macOS HFS+ volumes, though both are now rarely used.
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It also doesn't copy file permissions and metadata, though using
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:func:`shutil.copy2` instead will preserve most (though not all) of it.
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How do I read (or write) binary data?
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@ -252,20 +252,25 @@ Binary Data
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-----------
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It is perfectly possible to send binary data over a socket. The major problem is
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that not all machines use the same formats for binary data. For example, a
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Motorola chip will represent a 16 bit integer with the value 1 as the two hex
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bytes 00 01. Intel and DEC, however, are byte-reversed - that same 1 is 01 00.
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that not all machines use the same formats for binary data. For example,
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`network byte order <https://en.wikipedia.org/wiki/Endianness#Networking>`_
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is big-endian, with the most significant byte first,
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so a 16 bit integer with the value ``1`` would be the two hex bytes ``00 01``.
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However, most common processors (x86/AMD64, ARM, RISC-V), are little-endian,
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with the least significant byte first - that same ``1`` would be ``01 00``.
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Socket libraries have calls for converting 16 and 32 bit integers - ``ntohl,
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htonl, ntohs, htons`` where "n" means *network* and "h" means *host*, "s" means
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*short* and "l" means *long*. Where network order is host order, these do
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nothing, but where the machine is byte-reversed, these swap the bytes around
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appropriately.
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In these days of 32 bit machines, the ascii representation of binary data is
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In these days of 64-bit machines, the ASCII representation of binary data is
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frequently smaller than the binary representation. That's because a surprising
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amount of the time, all those longs have the value 0, or maybe 1. The string "0"
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would be two bytes, while binary is four. Of course, this doesn't fit well with
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fixed-length messages. Decisions, decisions.
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amount of the time, most integers have the value 0, or maybe 1.
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The string ``"0"`` would be two bytes, while a full 64-bit integer would be 8.
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Of course, this doesn't fit well with fixed-length messages.
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Decisions, decisions.
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Disconnecting
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@ -102,7 +102,7 @@ To map anonymous memory, -1 should be passed as the fileno along with the length
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To ensure validity of the created memory mapping the file specified
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by the descriptor *fileno* is internally automatically synchronized
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with physical backing store on macOS and OpenVMS.
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with the physical backing store on macOS.
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This example shows a simple way of using :class:`~mmap.mmap`::
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@ -53,7 +53,7 @@ Cross Platform
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.. function:: machine()
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Returns the machine type, e.g. ``'i386'``. An empty string is returned if the
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Returns the machine type, e.g. ``'AMD64'``. An empty string is returned if the
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value cannot be determined.
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@ -37,7 +37,7 @@ Large File Support
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.. sectionauthor:: Steve Clift <clift@mail.anacapa.net>
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Several operating systems (including AIX, HP-UX and Solaris) provide
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Several operating systems (including AIX and Solaris) provide
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support for files that are larger than 2 GiB from a C programming model where
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:c:type:`int` and :c:type:`long` are 32-bit values. This is typically accomplished
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by defining the relevant size and offset types as 64-bit values. Such files are
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@ -146,9 +146,10 @@ If the first character is not one of these, ``'@'`` is assumed.
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Native byte order is big-endian or little-endian, depending on the host
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system. For example, Intel x86 and AMD64 (x86-64) are little-endian;
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Motorola 68000 and PowerPC G5 are big-endian; ARM and Intel Itanium feature
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switchable endianness (bi-endian). Use ``sys.byteorder`` to check the
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endianness of your system.
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IBM z and most legacy architectures are big-endian;
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and ARM, RISC-V and IBM Power feature switchable endianness
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(bi-endian, though the former two are nearly always little-endian in practice).
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Use ``sys.byteorder`` to check the endianness of your system.
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Native size and alignment are determined using the C compiler's
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``sizeof`` expression. This is always combined with native byte order.
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