Question

我正在尝试将一个联合与pybind11绑定，并且遇到一个奇怪的错误。我不确定我是否遇到了pybind11的限制，或者我实现不正确。

有人能指出我正确的方向吗？谢谢！

#include <iostream>
#include <pybind11/pybind11.h>

namespace py = pybind11;

struct object {
   object();
   union union_type {
       bool boolean;
       uint64_t u64;
       int64_t  i64;
       double   f64;
   };
   union_type via;
};

PYBIND11_MODULE(example, m) {
    pybind11::class_<object, std::shared_ptr<object>> cl(m, "object", "Object class that corresponding stuff");
    pybind11::handle cl_type = cl;
    {
        auto & enclosing_class = cl;
        py::class_<object::union_type, std::shared_ptr<object::union_type>> cl(enclosing_class, "union_type", "");
        cl.def( pybind11::init( [](object::union_type const &o){ return new object::union_type(o); } ) );
        cl.def( pybind11::init( [](){ return new object::union_type(); } ) );
        cl.def_readwrite("boolean", &object::union_type::boolean);
        cl.def_readwrite("u64", &object::union_type::u64);
        cl.def_readwrite("i64", &object::union_type::i64);
        cl.def_readwrite("f64", &object::union_type::f64);
        cl.def("assign", (union object::union_type & (object::union_type::*)(const union object::union_type &)) &object::union_type::operator=, "C++: object::union_type::operator=(const union object::union_type &) --> union object::union_type &", pybind11::return_value_policy::automatic, pybind11::arg(""));
    }
}

错误：

pybind11/pybind11.h: In instantiation of ‘pybind11::class_<type_, options>& pybind11::class_<type_, options>::def_readwrite(const char*, D C::*, const Extra& ...) \
[with C = object::union_type; D = bool; Extra = {}; type_ = object::union_type; options = {std::shared_ptr<object::union_type>}]’:
mytest.cpp:35:59:   required from here
python3.7m/pybind11/pybind11.h:1161:9: error: static assertion failed: def_readwrite() requires a class member (or base class member
)
         static_assert(std::is_base_of<C, type>::value, "def_readwrite() requires a class member (or base class member)");
         ^~~~~~~~~~~~~

编辑-我使用：

c++ -O3 -Wall -shared -std=c++11 -fPIC `python3 -m pybind11 --includes` mytest.cpp -o example`python3-config --extension-suffix`

Answer 1

基于general union question with polakovicp's suggestion there ，您可以申请：

 typedef union _union_type {
       bool boolean;
       uint64_t u64;
       int64_t  i64;
       double   f64;
   }union_type;

py::class_<union_type>(m, "union_type")
        .def(py::init<>())
        .def_property("boolean",
            [](union_type& self) -> const bool& 
            {
                return self.boolean;
            },
            [](union_type& self, const bool& value)
            {
                self.boolean = value;
            });
        .def_property("u64",
            [](union_type& self) -> const uint64_t& 
            {
                return self.u64;
            },
            [](union_type& self, const uint64_t& value)
            {
                self.u64 = value;
            });
        .def_property("i64",
            [](union_type& self) -> const int64_t& 
            {
                return self.i64;
            },
            [](union_type& self, const int64_t& value)
            {
                self.i64 = value;
            });
        .def_property("f64",
            [](union_type& self) -> const double& 
            {
                return self.f64;
            },
            [](union_type& self, const int64_t& value)
            {
                self.f64 = value;
            });

pybind11联合失败'is_base_of'断言

1 个答案: