通过dll边界的C字符串 [英] C string through dll boundaries

问题描述

我们需要以安全的方式通过dll边界返回一个C字符串！我们该怎么做？

We need to return a C string through dll boundaries in a safe way! How can we do this?

我的想法：

extern "C" __declspec(dllexport) const char *const Api
{
    ...
    static const char *output = result.c_str();
    return output;
}

推荐答案

正在返回指针

如果结果变量（std :: string？）在堆栈中，则为函数返回时指针将被破坏，返回的指针将悬空-当然不是您想要的。

If the result variable (std::string?) is on the stack, it's going to be destroyed when the function returns and the returned pointer will be dangling -- certainly not what you want.

一种安全的方法是strdup（）响应，但调用者将负责释放C字符串。卸载DLL意味着返回的指针将悬空，除非它指向堆变量。

A safe way to do this is to strdup() the response, but then the caller will be responsible for freeing the C string. Unloading the DLL means that the returned pointer will be dangling unless it's pointing to a heap variable.

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