document streamlit c_types module dependency

[djudjuu]

UPDATE:

tldr: everything works fine, unless python has been built fom source without libffi support. (verified for ubuntu 24 and python 3.12 and 3.13), but to get to that point one has to ignore suggestions to install it.

Documentation description

streamlit interfaces with C functions, so your Python version must support that.

by default Linux has the libffi package installed, but not libffi-dev, which enables compilation from source. if python versions are installed with pyenv they then lack the ability to call c functions.

python -c "import _ctypes"

related: fix the error handling because its not graceful atm

Are you a dlt user?

None

[djudjuu]

We agreed that this is too special of a case to mention in the docs. having an issue that mentions _ctypes inthe title is also a kind of hint. If we ever open a common troubleshooting section it could go in there now.

for now we can close it