Good to hear. We have an RAII-type helper that we use in C++ to make it easier to acquire and release the GIL in functions that need it
https://github.com/apache/arrow/blob/master/cpp/src/arrow/python/common.h#L74 On Wed, Oct 28, 2020 at 2:08 PM James Thomas <jamesjoetho...@gmail.com> wrote: > > Thanks, Wes. Wrapping my C++ function with > > PyGILState_STATE state = PyGILState_Ensure(); > ... > PyGILState_Release(state); > > fixed the issue. > > On Wed, Oct 28, 2020 at 6:21 AM Wes McKinney <wesmck...@gmail.com> wrote: >> >> I haven't tried myself but my guess the problem is that your C++ >> function does not acquire the GIL. When ctypes invokes a native >> function, it releases the GIL. >> >> On Wed, Oct 28, 2020 at 4:29 AM James Thomas <jamesjoetho...@gmail.com> >> wrote: >> > >> > Hi, >> > >> > I am trying to run the following simple example after pip installing >> > pandas and pyarrow: >> > >> > ---cube.cpp--- >> > #include <Python.h> >> > #include <arrow/python/pyarrow.h> >> > #include <arrow/api.h> >> > >> > extern "C" void print_is_array(PyObject *); >> > >> > void print_is_array(PyObject *obj) { >> > arrow::py::import_pyarrow(); >> > printf("is_array: %d\n", arrow::py::is_array(obj)); >> > } >> > >> > ---cube.py--- >> > import ctypes >> > import pandas as pd >> > import pyarrow as pa >> > >> > c_lib = ctypes.CDLL("./libcube.so") >> > df = pd.DataFrame({"a": [1, 2, 3]}) >> > table = pa.Table.from_pandas(df) >> > c_lib.print_is_array(ctypes.py_object(table)) >> > >> > ---build.sh--- >> > #!/bin/bash >> > python3 -c 'import pyarrow; pyarrow.create_library_symlinks()' >> > INC=$(python3 -c 'import pyarrow; print(pyarrow.get_include())') >> > LIB=$(python3 -c 'import pyarrow; print(pyarrow.get_library_dirs()[0])') >> > g++ -I$INC -I/usr/include/python3.6m -fPIC cube.cpp -shared -o libcube.so >> > -L$LIB -larrow -larrow_python >> > >> > When I run build.sh and then do python3 cube.py, I am seeing a segfault at >> > the import_pyarrow() statement in cube.cpp. Am I doing something wrong >> > here? >> > >> > Thanks, >> > James
