从C调用优雅C ++ [英] Elegantly call C++ from C

问题描述

我们开发的纯 C （C99）的一些项目。但是，我们在 C ++ 一个库源$ C ​​$ CS（数学库）。我们需要这个库，所以我想问一下，什么是该源$ C ​​$ CS？

We develop some project in plain C (C99). But, we have one library as source codes (math library) in C++. We need this library so I would like to ask, what is the most elegant way to integrate this source codes?

C 和 C ++ 尺寸之比为 20：1 所以移动到 C ++ 是不是选项。我们是否应该用静态库？ DLL？ （这是所有在Windows上）。

Ratio between sizes of C and C++ is 20:1 so moving to C++ is not the option. Should we use static library? DLL? (It's all on Windows).

推荐答案

编辑：根据在评论的讨论，我要指出的是分离的东西变成一个C兼容结构鸭和派生类鸭可能是不必要的。你大概可以放心地铲落实到结构鸭和消除类鸭，从而避免实（...）。但我不知道的C ++不够好（特别是它与C宇宙的交互方式），以提供对这个一个明确的答案。

Based on discussion in the comment, I should point out that separating things into a C-compatible struct duck and a derived class Duck is probably unnecessary. You can probably safely shovel the implementation into struct duck and eliminate class Duck, thus obviating real(…). But I don't know C++ well enough (in particular, the way it interacts with the C universe) to offer a definitive answer on this.

有没有理由，你不能简单地连接所有的C和C ++ code连成一个单一的二进制。

There is no reason you can't simply link all your C and C++ code together into a single binary.

接口到C ++ code要求你包的C ++ API在C API。您可以通过声明一组函数里面的externC这样做{...}编译C ++ code时，没有extern声明编译时 C客户code。例如：

Interfacing to the C++ code requires that you wrap the C++ API in a C API. You can do this by declaring a bunch of functions inside extern "C" { ... } when compiling the C++ code, and without the extern declaration when compiling the C client code. E.g.:

#ifdef __cplusplus
extern "C" {
#endif

typedef struct duck duck;

duck* new_duck(int feet);
void delete_duck(duck* d);
void duck_quack(duck* d, float volume);

#ifdef __cplusplus
}
#endif

您可以在你的C ++源定义鸭结构，甚至继承了真正的烤鸭类从它：

You can define the duck struct in your C++ source, and even inherit the real Duck class from it:

struct duck { };

class Duck : public duck {
public:
    Duck(int feet);
    ~Duck();

    void quack(float volume);
};

inline Duck* real(duck* d) { return static_cast<Duck*>(d); }

duck* new_duck(int feet) { return new Duck(feet); }
void delete_duck(duck* d) { delete real(d); }
void duck_quack(duck* d, float volume) { real(d)->quack(volume); }

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