问如何在构建时设置cdll搜索路径？

EN

/* _custom.c */
#include <Python.h>
#include <dlfcn.h>

static struct PyModuleDef _custommodule = {
    PyModuleDef_HEAD_INIT,
    .m_name = "_custom",
    .m_doc = "Convenience module, libcustom.so wrapper",
    .m_size = -1
};

PyMODINIT_FUNC
PyInit__custom(void)
{
    PyObject *self = NULL, *ctypes = NULL, *cdll = NULL, *lib = NULL;

    /* We must import the library a first time here to allow the use
       of rpath. Otherwise `ctypes.cdll.LoadLibrary` uses dlopen from
       an internal python module, and the internal module's rpath will
       be used for link resolution instead of our. */
    if (! dlopen("libcustom.so", RTLD_NOW | RTLD_LOCAL)) {
        PyErr_SetString(PyExc_ImportError, dlerror());
        return NULL;
    }
    if (! (self = PyModule_Create(&_custommodule))) goto fail;
    if (! (ctypes = PyImport_ImportModule("ctypes"))) goto fail;
    if (! (cdll = PyDict_GetItemString(PyModule_GetDict(ctypes), (char*) "cdll"))) goto fail;
    if (! (lib = PyObject_CallMethod(cdll, "LoadLibrary", "s", "libcustom.so"))) goto fail;
    if (PyModule_AddObject(self, "_lib", lib) < 0) goto fail;

    Py_DECREF(ctypes);
    Py_DECREF(cdll);
    return self;

 fail:
    PyErr_SetString(PyExc_ImportError, "Internal error");
    Py_XDECREF(self);
    Py_XDECREF(ctypes);
    Py_XDECREF(cdll);
    Py_XDECREF(lib);
    return NULL;
}

# setup.py
setup(
    ext_modules=[Extension("mypackage._custom", ["_custom.c"])],
    ...
)

python3 setup.py build_ext --rpath /path/to/custom/lib
python3 setup.py install

#!/usr/bin/env python

import ctypes as ct
import os
import sys
from custom_dll_path import CUSTOM_DLL_PATH


DLL_NAME = "dll00.{:s}".format("dll" if sys.platform[:3].lower() == "win" else "so")


def main(*argv):
    if argv:
        dll_name = DLL_NAME
    else:
        dll_name = os.path.join(CUSTOM_DLL_PATH, DLL_NAME)
    print("Attempting to load: {:s}".format(dll_name))
    dll00 = ct.CDLL(dll_name)


if __name__ == "__main__":
    print("Python {:s} {:03d}bit on {:s}\n".format(" ".join(elem.strip() for elem in sys.version.split("\n")),
                                                   64 if sys.maxsize > 0x100000000 else 32, sys.platform))
    rc = main(*sys.argv[1:])
    print("\nDone.")
    sys.exit(rc)

#!/usr/bin/env python

import sys
from setuptools import Command, setup


class SetDllPath(Command):
    user_options = [
        ("path=", "p", "Dll path"),
    ]

    def initialize_options(self):
        self.path = ""

    def finalize_options(self):
        pass

    def run(self):
        with open("custom_dll_path.py", "w") as f:
            f.write("CUSTOM_DLL_PATH = \"{:s}\"\n".format(self.path))


setup(
    name="custom_project",
    cmdclass={
        "set_dll_path": SetDllPath,
    },
    #  Other stuff ...
)