1Caveats 2======= 3 4.. contents:: 5 :local: 6 7.. _python_caveat: 8 9Python 10------ 11 12LLDB has a powerful scripting interface which is accessible through Python. 13Python is available either from within LLDB through a (interactive) script 14interpreter, or as a Python module which you can import from the Python 15interpreter. 16 17To make this possible, LLDB links against the Python shared library. Linking 18against Python comes with some constraints to be aware of. 19 201. It is not possible to build and link LLDB against a Python 3 library and 21 use it from Python 2 and vice versa. 22 232. It is not possible to build and link LLDB against one distribution on 24 Python and use it through an interpreter coming from another distribution. 25 For example, on macOS, if you build and link against Python from 26 python.org, you cannot import the lldb module from the Python interpreter 27 installed with Homebrew. 28 293. To use third party Python packages from inside LLDB, you need to install 30 them using a utility (such as ``pip``) from the same Python distribution as 31 the one used to build and link LLDB. 32 33The previous considerations are especially important during development, but 34apply to binary distributions of LLDB as well. 35 36LLDB in Xcode on macOS 37`````````````````````` 38 39Users of lldb in Xcode on macOS commonly run into these issues when they 40install Python, often unknowingly as a dependency pulled in by Homebrew or 41other package managers. The problem is the symlinks that get created in 42``/usr/local/bin``, which comes before ``/usr/bin`` in your path. You can use 43``which python3`` to check to what it resolves. 44 45To be sure you use the Python that matches with the lldb in Xcode use ``xcrun`` 46or use the absolute path to the shims in ``/usr/bin``. 47 48:: 49 50 $ xcrun python3 51 $ /usr/bin/python3 52 53Similarly, to install packages and be able to use them from within lldb, you'll 54need to install them with the matching ``pip3``. 55 56:: 57 58 $ xcrun pip3 59 $ /usr/bin/pip3 60 61The same is true for Python 2. Although Python 2 comes with the operating 62system rather than Xcode, you can still use ``xcrun`` to launch the system 63variant. 64 65:: 66 67 $ xcrun python 68 $ /usr/bin/python 69 70Keep in mind that Python 2 is deprecated and no longer maintained. Future 71versions of macOS will not include Python 2.7. 72