DLL:导出为 C/C++ 函数? [英] DLL : export as a C/C++ function?

问题描述

我从 C++ 代码在 Visual 中生成了一个 DLL.Dependency Walker 看到 3 个函数导出为 C 函数.

I generated a DLL in Visual from a C++ code. Dependency Walker sees 3 functions exported as C functions.

我做了一个 SCons 项目来生成 DLL，3 个函数中有 2 个不是 C 函数.

I made an SCons project to do the generate the DLL, and 2 of the 3 functions are not seen as C functions.

是什么让函数被视为或 C++ 函数而不修改代码?它必须在编译/链接选项中，但我没有找到任何相关内容.

What makes a function seen as a or C++ function, without modifying the code ? It must be in the compilation/linking options, but I didn't find any relevant thing.

该函数以宏为前缀:AM_LIB_EXPORT

The function are prefixed by a macro : AM_LIB_EXPORT

在 .h 中，我有:

#ifdef _WIN32
#define AM_LIB_EXPORT __declspec(dllexport)
#else
#define AM_LIB_EXPORT
#endif // _WIN32

谢谢.

推荐答案

是什么让函数被视为或 C++ 函数而不修改代码?

What makes a function seen as a or C++ function, without modifying the code ?

由 C++ 编译器编译的函数自动成为C++ 函数"，并且会发生名称修改以解析 C++ 功能，例如命名空间和重载.为了获得C"导出名称，必须在函数声明中使用上述 extern "C" 限定符.或者，在包含原型的标题周围有一个巨大的 extern "C" { .. } 块.

A function compiled by a C++ compiler is automatically a 'C++-function' and name-mangling occurs to resolve C++ features such as namespaces and overloading. In order to get 'C' export names, one must use the aforementioned extern "C" qualifier in the function declaration. Alternatively a huge extern "C" { .. } block around the header containing the prototypes.

如果这不能解决您的问题，则可能与 dllimport/dllexport 有关.如果您在 DLL 构建中 #define AM_LIB_EXPORT __declspec(dllexport)，您通常还需要为链接到您的 DLL 的应用程序设置 dllimport，以便链接器知道从哪里获取符号.

If this does not solve your issue, its maybe related to dllimport/dllexport. If you #define AM_LIB_EXPORT __declspec(dllexport) in your DLL build, you'll typically also need to make it dllimport for apps linking against your DLL in order for the linker to know where to fetch the symbols from.

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