Question

我cmake一个项目，想在C ++项目中获得numpy数组。我可以获得正确的数字，但是它报告读取访问冲突。这是我的python代码，名为main.py

import numpy as np
import tensorflow as tf

class PyInterface(object):
    def __init__(self):
        self.X = None
        self.Y = None

    def generate_np_uint8(self):
        np_array = np.random.randint(low=0, high=255, size=(2,2,2),dtype=np.uint8);
        print("Python, uint8:", np_array)
        return np_array

    def generate_np_float32(self):
        np_array = np.random.rand(2,2,2).astype(np.float32)
        print("Python, float:", np_array)
        return np_array


if __name__ == '__main__':
    py = PyInterface();
    py.generate_np_uint8();
    py.generate_np_float32();

这是我用于扩展python的C ++代码

public:
float * CppPythonHandler::get_float() {
    return generate_np_float32();
}
private:
float * CppPythonHandler::generate_np_float32() {
    const int ND{3};
    float *c_out = new float[8];
    PyArrayObject *np_ret;
    PyObject* np_array = PyObject_CallMethod(interface, (const char*)"generate_np_float32", NULL, NULL);
    if (np_array) {
        np_ret = reinterpret_cast<PyArrayObject*>(np_array);
        if (PyArray_NDIM(np_ret) != ND) {
            std::cout << "Function returned with wrong dimension" << std::endl;
            Py_DECREF(np_array);
            Py_DECREF(np_ret);
            return c_out;
        }
        c_out[0] = *((float *)PyArray_GETPTR3(np_ret, 0, 0, 0));
        c_out[1] = *((float *)PyArray_GETPTR3(np_ret, 0, 0, 1));
        c_out[2] = *((float *)PyArray_GETPTR3(np_ret, 0, 1, 0));
        c_out[3] = *((float *)PyArray_GETPTR3(np_ret, 0, 1, 1));
        c_out[4] = *((float *)PyArray_GETPTR3(np_ret, 1, 0, 0));
        c_out[5] = *((float *)PyArray_GETPTR3(np_ret, 1, 0, 1));
        c_out[6] = *((float *)PyArray_GETPTR3(np_ret, 1, 1, 0));
        c_out[7] = *((float *)PyArray_GETPTR3(np_ret, 1, 1, 1));
        for (int i = 0; i < 8; ++i) {
            std::cout << c_out[i] << " ";
        }
        std::cout << std::endl;
        Py_DECREF(np_ret);
        Py_DECREF(np_array);
        return c_out;
    }
    else{
        PyErr_Print();
        Py_DECREF(np_array);
        Py_DECREF(np_ret);
        return c_out;
    }
}

这是我的main.cpp

static int numargs=0;

static PyObject*
emb_numargs(PyObject *self, PyObject *args)
{
    if(!PyArg_ParseTuple(args, ":numargs"))
        return NULL;
    return PyLong_FromLong(numargs);
}

static PyMethodDef EmbMethods[] = {
    {"numargs", emb_numargs, METH_VARARGS,
     "Return the number of arguments received by the process."},
    {NULL, NULL, 0, NULL}
};

static PyModuleDef EmbModule = {
    PyModuleDef_HEAD_INIT, "emb", NULL, -1, EmbMethods,
    NULL, NULL, NULL, NULL
};

static PyObject*
PyInit_emb(void)
{
    return PyModule_Create(&EmbModule);
}

int main(int argc, char *argv[]) {
    if (argc < 1) {
        fprintf(stderr,"Usage: call pythonfile funcname [args]\n");
        return 1;
    }

    numargs = argc;
    PyImport_AppendInittab("emb", &PyInit_emb);

    Py_Initialize();        // initialize python interpreter
    PyRun_SimpleString("import sys");
    PyRun_SimpleString("if not hasattr(sys, 'argv'):\n    sys.argv=['']");
    PyRun_SimpleString("sys.path.insert(0, \"./\")");
    PyRun_SimpleString("sys.path.insert(0, \"./venv/Lib\")");
    PyRun_SimpleString("sys.path.insert(0, \"./venv/Lib/site-packages\")");

    // instance cpp interface object
    CppPythonHandler * pInter = new CppPythonHandler("main", "PyInterface");
    // unsigned char * np_uint8 = pInter->get_uint8();
    float * np_float = pInter->get_float();

    std::cout<<"End test"<<std::endl;
    // delete []pInter;

    if (Py_FinalizeEx() < 0) {
        std::cout << "Fails to release" << std::endl;
        return 120;
    }
    system("pause");
    return 0;
}

在终端上，我看到我可以从python脚本中获得正确的值

从调用堆栈中我知道它在PyObject_Alloc中损坏

但是我仍然不是问题所在。谁能告诉我

EDIT1：这是我的构造函数

CppPythonHandler::CppPythonHandler(const char* pModuleName, const char* pClassName) {
    interfaceModule = NULL;
    interfaceClass = NULL;
    interface = NULL;
    interfaceModule = PyImport_ImportModule(pModuleName);
    if (interfaceModule == NULL) {
        PyErr_Print();
        fprintf(stderr,"Fails to import the module.\n");
        Py_DECREF(interfaceModule);
    }
    else{
        // import interface class
        interfaceClass = PyObject_GetAttrString(interfaceModule, pClassName);
        if (interfaceClass && PyCallable_Check(interfaceClass)) {

            // NULL represents no args
            interface = PyObject_CallObject(interfaceClass, NULL);
            Py_DECREF(interfaceClass);
            Py_DECREF(interfaceModule);
            if(interface == NULL){
                fprintf(stderr,"Fails to instance interface.\n");
                Py_DECREF(interface);
            }
            std::cout<<"Initailization done"<<std::endl;
        }
        else{
            if (PyErr_Occurred())
                PyErr_Print();
            fprintf(stderr,"Fails to import the class.\n");
            Py_DECREF(interfaceClass);
            Py_DECREF(interfaceModule);
        }
    }
}

interfaceModule，interfaceClass和interface是私有的PyObject *

EDIT2：这是PyObject_Alloc的局部参数

Answer 1

我也遇到了同样的错误消息，并且几乎是偶然地设法修复了它。

摘要：这似乎是由引用计数错误的PyObject *引起的。错误发生时使用的PyObject不一定是引用计数错误的对象！读https://docs.python.org/3/c-api/intro.html#objects-types-and-reference-counts可能会有所帮助。

就我而言，我的C ++正在从从python函数获得的PyObject列表中读取项目。但是，当从列表中读取这些项目时，其引用计数并未增加，因为我正在调用PyList_GetItem()而不是PySequence_GetItem()。调试起来很痛苦，因为错误是从运行PyObject_CallFunction()的完全不相关的代码部分抛出的。

希望这会有所帮助！

引发异常：读取访问冲突。 bp 为0xFFFFFFFFFFFFFFFFFF

1 个答案:

引发异常：读取访问冲突。 ** bp **为0xFFFFFFFFFFFFFFFFFF

1 个答案:

引发异常：读取访问冲突。 bp 为0xFFFFFFFFFFFFFFFFFF