[英]C++: struct forward declaration of anonymous struct causes "conflicting declaration"
I have got this hpp file:我有这个 hpp 文件:
struct rte_spinlock_t;
class A {
public:
void init();
private:
rte_spinlock_t* spinlock;
};
and the corresponding cpp file:以及对应的cpp文件:
#include "A.hpp"
typedef struct {
int lock;
} rte_spinlock_t;
void A::init()
{
}
Now, compiling like this: g++ A.cpp I get this error:现在,像这样编译:g++ A.cpp 我得到这个错误:
A.cpp:5:3: error: conflicting declaration ‘typedef struct rte_spinlock_t rte_spinlock_t’
5 | } rte_spinlock_t;
| ^~~~~~~~~~~~~~
In file included from A.cpp:1:
A.hpp:2:8: note: previous declaration as ‘struct rte_spinlock_t’
2 | struct rte_spinlock_t;
| ^~~~~~~~~~~~~~
Obviously making the struct named it works, unfortunately I cannot control the typedef of struct rte_spinlock_t that is in a library.显然使命名它的结构有效,不幸的是我无法控制库中 struct rte_spinlock_t 的 typedef。
How could I workaround this?我该如何解决这个问题?
I expect to be able to forward an unnamed struct without getting into conflicting declaration.我希望能够转发一个未命名的结构而不会陷入声明冲突。
From what I understand what you have is more-less this (erroneous code): https://godbolt.org/z/zarsTq6oE据我了解,您所拥有的更多(错误代码): https://godbolt.org/z/zarsTq6oE
Why don't you use pimpl (private implementation) idiom for extra level of indirection and hiding the "gory details"?为什么不使用 pimpl(私有实现)成语来进行额外级别的间接访问并隐藏“血淋淋的细节”?
Let's assume my X
is your A
, lib.h
contains the troublesome typedef:假设我的
X
是你的A
, lib.h
包含麻烦的 typedef:
//example.cpp
#include "example.hpp"
#include "lib.h"
struct Impl
{
CStruct* cs;
};
void X::init()
{
clib_init(&impl->cs);
}
X::X()
{
impl = std::make_unique<Impl>();
}
X::~X() = default;
//example.hpp
#pragma once
#include <memory>
struct Impl;
struct X
{
X();
~X();
//rest of special functions omitted for brevity
//feel free to add them at your own leisure
void init();
std::unique_ptr<Impl> impl;
};
Live demo: https://godbolt.org/z/4jYGrYEjr现场演示: https://godbolt.org/z/4jYGrYEjr
BTW, I made an assumption that your troublesome struct is C code based on some searching...顺便说一句,我假设你的麻烦结构是基于一些搜索的 C 代码......
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