(CLASS*)int to shared_ptr<CLASS>(int) not work

Question

I want to convert the source to a smart pointer. But I found one I don’t understand why it can’t. How can this be solved with the code below?

Old code style:

bool PyTuple_GetTextInstance(PyObject* poArgs, int pos, CGraphicTextInstance** ppTextInstance)
{
    int handle;
    if (!PyTuple_GetInteger(poArgs, pos, &handle))
        return false;

    if (!handle)
        return false;

    *ppTextInstance=(CGraphicTextInstance*)handle;

    return true;
}

new code style:

bool PyTuple_GetTextInstance(PyObject* poArgs, int pos, std::shared_ptr<CGraphicTextInstance>& ppTextInstance)
{
    int handle;
    if (!PyTuple_GetInteger(poArgs, pos, &handle))
        return false;

    if (!handle)
        return false;

    ppTextInstance=std::static_pointer_cast<CGraphicTextInstance>(handle);

    return true;
}

why not work? problem: std::static_pointer_cast error

invitation:

PyObject* grpTextGetSize(PyObject* poSelf, PyObject* poArgs)
{
    CGraphicTextInstance* pTextInstance;
    if (!PyTuple_GetTextInstance(poArgs, 0, &pTextInstance))
        return Py_BuildException();

    int width, height;
    pTextInstance->GetTextSize(&width, &height);
    return Py_BuildValue("(i, i)", width, height);
}

PyTuple_GetInteger function:

bool PyTuple_GetInteger(PyObject* poArgs, int pos, int* ret)
{
    if (pos >= PyTuple_Size(poArgs))
        return false;

    PyObject* poItem = PyTuple_GetItem(poArgs, pos);

    if (!poItem)
        return false;

    *ret = PyLong_AsLong(poItem);
    return true;
}

Answer 1

Assuming that the original code is correct and that handle is really a pointer to a CGraphicTextInstance under the skin, then you need to replace this:

ppTextInstance=std::static_pointer_cast<CGraphicTextInstance>(handle);

with this:

ppTextInstance = std::shared_ptr <CGraphicTextInstance>
    (reinterpret_cast <CGraphicTextInstance *> (handle));

But it would be cleaner for this function to return a shared_ptr <CGraphicTextInstance>, with the wrapped pointer set to nullptr on failure.