在我的程序中,我在C ++中管理对python对象的引用。即我的所有类都是从Referenced类派生的,它包含指向相应python对象的指针。
class Referenced
{
public:
unsigned use_count() const
{
return selfptr->ob_refcnt;
}
void add_ref() const
{
Py_INCREF(selfptr);
}
void remove_ref() const
{
Py_DECREF(selfptr);
}
PyObject* selfptr;
};
我使用intrusive_ptr来保存从Referenced派生的对象。这使我可以轻松地在C ++中保持对所需python对象的引用,并在必要时访问它们。但是当我要从C ++中删除python对象时,我的程序崩溃(仅在windows howewer中),即当我调用Py_DECREF(selfptr)时,是否selfptr-> ob_refcnt == 1. 这种方法是否正常?
更新:我终于找到了程序中的问题。它与对象移除无直接关系。为了检查最初的问题,我已经实现了简单的扩展模块,记住对python对象的引用并按需发布它。这是它:
#include <Python.h>
static PyObject* myObj;
static PyObject* acquirePythonObject(PyObject* self, PyObject* obj)
{
printf("trying to acquire python object %p, refcount = %d\n", obj, obj->ob_refcnt);
myObj = obj;
Py_INCREF(myObj);
printf("reference acquired\n");
return Py_True;
}
static PyObject* freePythonObject(PyObject*, PyObject*)
{
printf("trying to free python object %p, refcount = %d\n", myObj, myObj->ob_refcnt);
Py_DECREF(myObj);
printf("reference removed\n");
return Py_True;
}
static PyMethodDef moduleMethods[] =
{
{"acquirePythonObject", acquirePythonObject, METH_O, "hold reference to python object."},
{"freePythonObject", freePythonObject, METH_NOARGS, "free reference to python object."},
{NULL, NULL, 0, NULL}
};
PyMODINIT_FUNC initmodule(void)
{
Py_InitModule("module", moduleMethods);
}
和python脚本:
import module
class Foo:
def __init__(self):
print "Foo is created"
def __deinit__(self):
print "Foo is destroyed"
def acquireFoo():
foo = Foo()
module.acquirePythonObject(foo)
def freeFoo():
module.freePythonObject()
if __name__ == "__main__":
acquireFoo()
freeFoo()
示例在Windows和Linux中无缝运行。以下是输出。
Foo is created
trying to acquire python object 0x7fa19fbefd40, refcount = 2
reference acquired
trying to free python object 0x7fa19fbefd40, refcount = 1
Foo is destoryed
reference removed
答案 0 :(得分:1)
这种方法可以吗?
基本上,但是......
add_ref
/ remove_ref
被称为正确的次数(使用RAII会自动执行此操作 - 也许这就是你的intrusive_ptr的作用?)remove_ref
太多次,我不确定Python保证什么。如果您知道refcount从1开始设置selfptr = NULL
- > 0,你可以抓住这个
Py_XDECREF
Py_CLEAR
代替最后......你有任何崩溃转储或诊断信息吗?