René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"`getfilesystemencoding()` returns incorrect value on Linux","articleBody":"There seems to be a discrepancy between pythonnet and system-installed python when determining the file-system-encoding.\n\nThis is my pythonnet code:\n\n```cs\n        Runtime.PythonDLL = \"/usr/lib/x86_64-linux-gnu/libpython3.12.so\";\n        PythonEngine.Initialize();\n        PythonEngine.BeginAllowThreads();\n\n        using (Py.GIL())\n        {\n            dynamic sys = Py.Import(\"sys\");\n            Console.WriteLine(\"Filesystem encoding: {0}\", sys.getfilesystemencoding());\n            Console.WriteLine(\"Default encoding: {0}\", sys.getdefaultencoding());\n        }\n```\n\nWhich prints:\n\n```\nFilesystem encoding: ascii\nDefault encoding: utf-8\n```\n\nHowever, this is not correct! First, it only prints this on Linux. On windows, the filesystem-encoding is correctly determined to be 'utf-8'. Running a simple oneliner in python itself returns the correct values on both platforms:\n\n```\n$ python -c \"import sys; print(sys.getfilesystemencoding()); print(sys.getdefaultencoding())\"\nutf-8\nutf-8\n```\n\nThe python-version is 3.12.3, the dotnet version is 8.0.408 on both platforms as well.\n\nI've tried to work around this with environment variables, but those aren't recognized as expected, see https://github.com/pythonnet/pythonnet/discussions/2539#discussioncomment-15095791\n\nAnother option might be to call [`PySys_AddXOption`](https://docs.python.org/3.11/c-api/sys.html#c.PySys_AddXOption) with [\"utf8\" to set UTF-8 Mode manually](https://docs.python.org/3.11/library/os.html#utf8-mode:~:text=It%20can%20be%20enabled%20or%20disabled%20using%20the%20%2DX%20utf8%20command%20line%20option), but pythonnet has no binding for this function.\n\nI'm at a loss about what to do next. This seems like a genuine bug, so I opened this here instead of starting a discussion.","author":{"url":"https://github.com/iFreilicht","@type":"Person","name":"iFreilicht"},"datePublished":"2025-11-27T10:59:54.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/2664/pythonnet/issues/2664"}