在指向成员的指针之间转换

我知道您不能将指向成员的指针转换为指向非成员的指针(例如。, void* ),但能否在指向同一类的成员的指针之间进行转换?E、 例如:对于某些班级 C 和类型 T 和 U ,你能把 T C::* 到 U C::* ?

我希望能够将字符串名称映射到某个类的指向成员的指针。例如,给定:

template<class ClassType>
struct mbr_map_traits {
    typedef std::string mbr_name_type;
    typedef void* ClassType::*any_mbr_ptr;
    typedef std::map<mbr_name_type,any_mbr_ptr> map_type;
};

/**
 * A %mbr_map is used to map a string to an arbitrary pointer-to-member of some class.
 * @tparam ClassType The class whose members to map to.
 */
template<class ClassType>
struct mbr_map : mbr_map_traits<ClassType>::map_type {
    typedef typename mbr_map_traits<ClassType>::mbr_name_type mbr_name_type;

    /**
     * Initalizes an entry in the map so as to mape \a name to a pointer-to-member.
     * @param name The name to map.
     * @param p    The pointer-to-member to map to.
     */
    template<typename MemberType>
    void mbr_init( mbr_name_type const &name, MemberType ClassType::*p ) {
        typedef typename mbr_map_traits<ClassType>::any_mbr_ptr any_mbr_ptr;
        (*this)[ name ] = reinterpret_cast<any_mbr_ptr>( p );      // IS THIS OK?
    }

    /**
     * Sets the value of a class member by name.
     * @param c     The class whose member to set.
     * @param name  The name of the class member to set.
     * @param value The value to set the member to.
     * @return true only if \a name exists in the map.
     */
    template<typename MemberType>
    bool mbr_set( ClassType &c, mbr_name_type const &name, MemberType const &value ) {
        typedef typename mbr_map<ClassType>::const_iterator const_iterator;
        const_iterator const found = this->find( name );
        if ( found != this->end() ) {
            typedef MemberType ClassType::*mbr_ptr;
            c.*reinterpret_cast<mbr_ptr>( found->second ) = value; // IS THIS OK?
            return true;
        }
        return false;
    }
};

以及一些一次性初始化:

struct S {
    std::string s;
    int i;
    bool b;
};

void mbr_map_init( mbr_map<S> *m ) {
    m->mbr_init( "string_mbr", &S::s );
    m->mbr_init( "int_mbr", &S::i );
    m->mbr_init( "bool_mbr", &S::b );
}

我可以做到这一点:

using namespace std;

int main() {
    mbr_map<S> m;
    mbr_map_init( &m );

    S s;

    m.mbr_set( s, "string_mbr", string( "hello" ) );
    m.mbr_set( s, "int_mbr", 42 );
    m.mbr_set( s, "bool_mbr", true );

    cout << s.s << endl;
    cout << s.i << endl;
    cout << s.b << endl;
    return 0;
}

它会打印我设置的值。但这是 合法的 ?

(我想这样做的原因是将从配置文件读取的参数名称和值映射到结构成员。)