Function npy_PyErr_ChainExceptionsCause

numpy/core/include/numpy/npy_3kcompat.h:475–500

This is a copy of _PyErr_ChainExceptions, with: * - a minimal implementation for python 2 * - __cause__ used instead of __context__ */

 *  - __cause__ used instead of __context__
 */
static inline void
npy_PyErr_ChainExceptionsCause(PyObject *exc, PyObject *val, PyObject *tb)
{
    if (exc == NULL)
        return;

    if (PyErr_Occurred()) {
        /* only py3 supports this anyway */
        #ifdef NPY_PY3K
            PyObject *exc2, *val2, *tb2;
            PyErr_Fetch(&exc2, &val2, &tb2);
            PyErr_NormalizeException(&exc, &val, &tb);
            if (tb != NULL) {
                PyException_SetTraceback(val, tb);
                Py_DECREF(tb);
            }
            Py_DECREF(exc);
            PyErr_NormalizeException(&exc2, &val2, &tb2);
            PyException_SetCause(val2, val);
            PyErr_Restore(exc2, val2, tb2);
        #endif
    }
    else {
        PyErr_Restore(exc, val, tb);
    }
}

/*
 * PyObject_Cmp