cdleary/bazel_pybind_sample

Simple example of using pybind11 via Bazel.

Bazel / pybind11 sample

Simple, working pybind11-via-bazel example on Linux/x64 (tested on Ubuntu).

Background info provided by:

• pybind11 basics: https://pybind11.readthedocs.io/en/stable/basics.html
• pybind11_bazel readme: https://github.com/pybind/pybind11_bazel

If you're observing segfaults, it may be that the DSO is being built for Python2 while the bazel test interpreter is Python 3.

You can observe what Python headers were used for building by observing the file in a path similar to:

bazel-out/k8-fastbuild/bin/external/local_config_python/python_include/patchlevel.h

And you can help point at the right Python binary by providing it to the python_configure.bzl script in pybind11_bazel through an environment variable:

PYTHON_BIN_PATH=/usr/bin/python3 bazel test -c dbg :example_test --test_output=all

bazel_pybind_sample's Issues

symbol not found in flat namespace errors on Mac OSX

I have not been able to get this example to work on my computer. I am using an Apple M1 computer, and consistently get

Traceback (most recent call last): File "/private/var/tmp/_bazel_connie/f24ab60b302356e3037695b783d4e5e0/sandbox/darwin-sandbox/74/execroot/__main__/bazel-out/darwin_arm64-dbg/bin/example_test.runfiles/__main__/example_test.py", line 9, in <module> import my_pb_mod ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/my_pb_mod-1.0.1-py3.10-macosx-10.9-universal2.egg/my_pb_mod.cpython-310-darwin.so, 0x0002): symbol not found in flat namespace '_PyInt_FromSsize_t'

I have been able to install it through g++ with the following command:
g++ -O3 -Wall -shared -std=c++17 -undefined dynamic_lookup $(python3 -m pybind11 --includes) my_pb_mod.cc -o example $(python3-config --extension-suffix), but I have not been able to install it through Bazel.

I thought it might be a seg fault issue with the dynamic library, but I ran the troubleshooting environmental variable PYTHON_BIN_PATH with Python 2.7 and 3.8, both result in the same error.

Has anyone fixed the issue with the symbol not found in flat namespace?