:mod:`struct` -- pack and unpack primitive data types
=====================================================

.. module:: struct
   :synopsis: pack and unpack primitive data types

|see_cpython_module| :mod:`python:struct`.

Supported size/byte order prefixes: ``@``, ``<``, ``>``, ``!``.

Supported format codes: ``b``, ``B``, ``h``, ``H``, ``i``, ``I``, ``l``,
``L``, ``q``, ``Q``, ``s``, ``P``, ``f``, ``d`` (the latter 2 depending
on the floating-point support).

.. admonition:: Difference to CPython
   :class: attention

   Whitespace is not supported in format strings.

Functions
---------

.. function:: calcsize(fmt)

   Return the number of bytes needed to store the given *fmt*.

.. function:: pack(fmt, v1, v2, ...)

   Pack the values *v1*, *v2*, ... according to the format string *fmt*.
   The return value is a bytes object encoding the values.

.. function:: pack_into(fmt, buffer, offset, v1, v2, ...)

   Pack the values *v1*, *v2*, ... according to the format string *fmt*
   into a *buffer* starting at *offset*. *offset* may be negative to count
   from the end of *buffer*.

.. function:: unpack(fmt, data)

   Unpack from the *data* according to the format string *fmt*.
   The return value is a tuple of the unpacked values.

.. function:: unpack_from(fmt, data, offset=0, /)

   Unpack from the *data* starting at *offset* according to the format string
   *fmt*. *offset* may be negative to count from the end of *buffer*. The return
   value is a tuple of the unpacked values.
