Docs: Add explanation about little/big endian (python#109841)

Granjow · AA-Turner · hauntsaninja · woodruffw · commit baa7d89d2e12 · 2024-03-04T14:02:53.000-05:00
Co-authored-by: Adam Turner &lt;9087854+AA-Turner@users.noreply.github.com&gt;
Co-authored-by: Shantanu &lt;12621235+hauntsaninja@users.noreply.github.com&gt;
diff --git a/Doc/library/struct.rst b/Doc/library/struct.rst
@@ -160,6 +160,21 @@ following table:
 
 If the first character is not one of these, ``'@'`` is assumed.
 
+.. note::
+
+   The number 1023 (``0x3ff`` in hexadecimal) has the following byte representations:
+
+   * ``03 ff`` in big-endian (``>``)
+   * ``ff 03`` in little-endian (``<``)
+
+   Python example:
+
+       >>> import struct
+       >>> struct.pack('>h', 1023)
+       b'\x03\xff'
+       >>> struct.pack('<h', 1023)
+       b'\xff\x03'
+
 Native byte order is big-endian or little-endian, depending on the
 host system. For example, Intel x86, AMD64 (x86-64), and Apple M1 are
 little-endian; IBM z and many legacy architectures are big-endian.
