comtypes

comtypes

comtypes is a lightweight pure Python COM package based on the ctypes foreign function interface library.

comtypes allows you to define, call, and implement custom and dispatch-based COM interfaces in pure Python.

comtypes requires Windows and Python 3.9 or later.

• Note about Python 3.15 and enum behavior
  Starting with Python 3.15, the internal handling of IntFlag(Flag) values is planned to change:
  Negative IntFlag members will be reinterpreted by masking them to the defined positive bit domain, instead of keeping their original negative literal values.
  This can affect enumeration types generated by comtypes from COM type libraries. Action is needed to maintain literal evaluation.
  For details and ongoing discussion, see: GH-894.
• Version 1.4.12 is the last version to support Python 3.8.
• Version <= 1.4.7 does not work with Python 3.13 as reported in GH-618. Version 1.4.8 can work with Python 3.13.
• Version 1.4.6 is the last version to support Python 3.7.
• Version 1.2.1 is the last version to support Python 2.7 and 3.3–3.6.
• Certain comtypes functions may not work correctly in Python 3.8 and 3.9 as reported in GH-212. This bug has been fixed in Python >= 3.10.10 and >= 3.11.2.

Installation

comtypes is available on PyPI and can be installed with pip:

# PyPI
pip install comtypes

The source code is currently hosted here on GitHub.

Dependencies

comtypes is a pure Python package — it has no additional required dependencies.

Optional functionalities can be enabled by installing:

• numpy, in order to process arrays as numpy's ndarray.
• mypy or other static type checkers, in order to interpret type hints.

None of these packages, however, are required in order to run comtypes.

Community

The GitHub repository is used for tracking issues, reporting bugs, and contributing to the codebase and documentation.

For Enterprise

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Frequently Asked Questions

Q: Why does this package not support platforms other than Windows?

A: The Microsoft Component Object Model (COM) is a technology that is unique to Windows and is not supported on other platforms.

The phrase "COM is a platform-independent" in the MS documentation means that COM maintains compatibility across different versions of Windows, and does NOT imply that it is supported on Linux or Mac.

For as long as COM is not supported outside of Windows, there is no plan to port comtypes to other platforms.

Q: Why does cannot import name 'COMError' from '_ctypes' error occur when using this package on platforms other than Windows?

A: The _ctypes is part of the internal implementation of the ctypes standard library that exists for Python on all platforms. However, COMError and COM-related features are only implemented in Python for Windows.

In cross-platform software development, care must be taken to ensure that codebases that depend on comtypes do not execute in environments other than Windows.

Q: Despite a script that depends on comtypes having run successfully before, a error (ImportError, NameError, or SyntaxError) is raised now, and the same error occurs again and again.

A: Executing py -m comtypes.clear_cache and then running the script again might resolve the problem.

When comtypes.client.GetModule is called (either directly or indirectly), comtypes generates Python module files.
If Python is forced to terminate or crashes in the middle of file generation, the codebase written to the file becomes partial.
When Python tries to import this unexecutable partial codebase module, an error occurs.

Executing py -m comtypes.clear_cache identifies the directories where the "cache module files" are stored and deletes them.
After deleting these partial modules and running the script again, comtypes.client.GetModule is called and executable modules are generated anew.

However, if the script implementation does not use comtypes.client.GetModule or processes generated files, it may not be a solution.

Documentation

The documentation is currently hosted here on ReadTheDocs.