1Caveats 2======= 3 4.. _python_caveat: 5 6Python 7------ 8 9LLDB has a powerful scripting interface which is accessible through Python. 10Python is available either from within LLDB through a (interactive) script 11interpreter, or as a Python module which you can import from the Python 12interpreter. 13 14To make this possible, LLDB links against the Python shared library. Linking 15against Python comes with some constraints to be aware of. 16 171. It is not possible to build and link LLDB against a Python 3 library and 18 use it from Python 2 and vice versa. 19 202. It is not possible to build and link LLDB against one distribution on 21 Python and use it through an interpreter coming from another distribution. 22 For example, on macOS, if you build and link against Python from 23 python.org, you cannot import the lldb module from the Python interpreter 24 installed with Homebrew. 25 263. To use third party Python packages from inside LLDB, you need to install 27 them using a utility (such as ``pip``) from the same Python distribution as 28 the one used to build and link LLDB. 29 30The previous considerations are especially important during development, but 31apply to binary distributions of LLDB as well. 32 33LLDB in Xcode on macOS 34`````````````````````` 35 36Users of lldb in Xcode on macOS commonly run into these issues when they 37install Python, often unknowingly as a dependency pulled in by Homebrew or 38other package managers. The problem is the symlinks that get created in 39``/usr/local/bin``, which comes before ``/usr/bin`` in your path. You can use 40``which python3`` to check to what it resolves. 41 42To be sure you use the Python that matches with the lldb in Xcode use ``xcrun`` 43or use the absolute path to the shims in ``/usr/bin``. 44 45:: 46 47 $ xcrun python3 48 $ /usr/bin/python3 49 50Similarly, to install packages and be able to use them from within lldb, you'll 51need to install them with the matching ``pip3``. 52 53:: 54 55 $ xcrun pip3 56 $ /usr/bin/pip3 57 58The same is true for Python 2. Although Python 2 comes with the operating 59system rather than Xcode, you can still use ``xcrun`` to launch the system 60variant. 61 62:: 63 64 $ xcrun python 65 $ /usr/bin/python 66 67Keep in mind that Python 2 is deprecated and no longer maintained. Future 68versions of macOS will not include Python 2.7. 69