Dummy ubyteslib module for Pycopy

python, micropython, minimalist, suckless, pycopy
pip install pycopy-ubyteslib==0.0.0



pycopy-lib is a project to develop a non-monolothic standard library for the Pycopy project (, while where possible, staying compatible with other variants and implementations of Python. The goals of the project are:

  • As the main goal, develop Pycopy standard library as close as possible matching that of CPython. It thus necessarily targets "Unix" port of Pycopy.
  • As a side goal, develop individual modules usable/useful on baremetal ports of Pycopy. This is oftentimes conflicts with the first goal (something as close as possible matching CPython functionality is just too big to run on low-memory systems), and necessitates creation of additional modules, or special "micro" (aka "u") versions of them.

Each module or package of pycopy-lib is available as a separate distribution package from PyPI. Each module comes from one of the following sources (and thus each module has its own licensing terms):

  • written from scratch specifically for Pycopy
  • ported from CPython
  • ported from some other Python implementation, e.g. PyPy
  • some modules actually aren't implemented yet and are dummy
  • some modules are extensions and are not part of CPython's standard library

As mentioned above, the main target of pycopy-lib is the "Unix" port of Pycopy. Actual system requirements vary per module. Majority of modules are compatible with MicroPython, though some may require additional functionality/optimizations present in Pycopy. Modules not related to I/O may also work without problems on bare-metal ports, not just on "Unix" port (e.g. esp8266).


pycopy-lib packages are published on PyPI (Python Package Index), the standard Python community package repository: . On PyPI, you can search for Pycopy related packages and read additional package information. By historical convention, all pycopy-lib package names are prefixed with "micropython-" (the reverse is not true - some package starting with "micropython-" aren't part of pycopy-lib and are released by 3rd parties).

Browse available packages via this URL. (Note: this may also include 3rd-party modules which are not part of pycopy-lib.)

To install packages from PyPI for usage on your local system, use the upip tool, which is Pycopy's native package manager, similar to pip, which is used to install packages for CPython. upip is bundled with Pycopy "Unix" port (i.e. if you build "Unix" port, you automatically have upip tool). Following examples assume that micropython binary is available on your PATH:

$ micropython -m upip install micropython-pystone
$ micropython
>>> import pystone
>>> pystone.main()
Pystone(1.2) time for 50000 passes = 0.534
This machine benchmarks at 93633 pystones/second

Run micropython -m upip --help for more information about upip.

CPython backports

While pycopy-lib focuses on Pycopy, sometimes it may be beneficial to run Pycopy code using CPython, e.g. to use code coverage, debugging, etc. tools available for it. To facilitate such usage, pycopy-lib also provides reimplementations ("backports") of Pycopy modules, which run on CPython. This first of all applies to the builtin Pycopy "u" modules, but as time goes on, backports of pycopy-lib's own modules can be provided. Backport modules are in the directories named cpython-* of this repository. On PyPI, these named micropython-cpython-*.

These modules should be installed with CPython's pip3 tool. Example session:

$ pip3 install --user micropython-cpython-uhashlib
$ python3
>>> import uhashlib
>>> uhashlib.sha1(b"test").hexdigest()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'sha1' object has no attribute 'hexdigest'
# MicroPython's uhashlib doesn't have hexdigest(), use ubinascii.hexlify(.digest())
>>> uhashlib.sha1(b"test").digest()


To install modules during development, use make install. By default, all available packages will be installed. To install a specific module, add the MOD=<module> parameter to the end of the make install command.


pycopy-lib is a community project and can be implemented "fully" only by contributions from interested parties. The contributions are expected to adhere to Contribution Guidelines.


If you would like to trace evolution of Pycopy packaging support (which initially started in MicroPython project), you may find following links useful (note that they may contain outdated information):

Guidelines for packaging MicroPython modules for PyPI:


pycopy-lib is developed and maintained by Paul Sokolovsky (@pfalcon) with the help of Pycopy/MicroPython community.

List of modules specific to pycopy-lib

While pycopy-lib's primary way is to provide implementation of Python standard library, pycopy-lib goes further and hosts some extension modules which are deemed to be worth being a part of "Pycopy standard library". This section lists them to easy discovery:

  • uaiohttpclient - HTTP client for uasyncio
  • uargparse - small subset of argparse module
  • uasyncio - asynchronous scheduling and I/O, roughly based on CPython's asyncio
  • uasyncio.core - just a scheduler part of uasyncio
  • uasyncio.queues - subset of CPython's asyncio.Queue
  • uasyncio.synchro - synchronization primitives for uasyncio (subset of asyncio's)
  • uasyncio.udp - UDP support for uasyncio
  • ucontextlib - subset of contextlib functionality
  • uctypelib - higher-level helpers to define structure for the builtin uctype module
  • uctypeslib2 - pretty printing support for uctypes structure definitions
  • ucurses - small subset of curses module
  • udnspkt - DNS packet handling (Sans I/O approach)
  • ulogging - small subset of logging module
  • umqtt.robust
  • umqtt.simple
  • upip - Pycopy package manager, modelled after "pip" tool
  • upysh - minimalistic filesystem shell using Python syntax
  • urequests - subset of "requests" module
  • urlib.urequest - small subset of urlib.request module
  • utarfile - small subset of tarfile module
  • utokenize - simple tokenizer for Python source
  • uurequests - very small subset of "requests" module
  • uwwwauth - HTTP Basic/Digest authentication algorithms
  • xmltok2 - small/simple XML tokenizer