来自C ++源代码的C-DLL [英] C-DLL from C++ source

问题描述

我的C ++框架有一个C-Wrapper.由于这应该可以在Mac和Windows上运行，因此我使用的是 scons :

I have a C-Wrapper for my C++ Framework. Since this should run on mac and windows I am using scons:

env = Environment()
env.Append(CPPPATH = ['./'])
env.Append(LIBS = 'kernel32.lib')
env.Append(LIBPATH = 'C:/Program Files/Microsoft SDKs/Windows/v6.0A/Lib')

env.SharedLibrary(target='warpLib', source='warplib.cpp')

warplib.cpp和warplib.h的简单版本如下:

Simple Versions of warplib.cpp and warplib.h look like this:

warplib.cpp

#define DllExport __declspec( dllexport )
#include "warplib.h"

extern "C" {
  DllExport int foo(int a) {
    return a;
  }
}

warplib.h

#define DllExport __declspec( dllexport )

extern "C" {
  DllExport int foo(int a);
}

有人可以告诉我这是怎么回事吗?我尝试了几乎所有可能使用'extern"C"的组合，但是它总是使我感到类似错误C2732:链接规范与早期的'...'规范相矛盾".

Can anybody tell me what is wrong with that? I tried almost all the combinations possible of 'extern "C"' but it always throws me something like "error C2732: linkage specification contradicts earlier specification for '...'".

如果我跳过'extern"C"，它可以工作，但是看不到.lib文件，我很确定我真的需要使用该库.

If I skip 'extern "C"' it works but I see no .lib file and I am pretty sure I need that to really use the library.

推荐答案

您只需要在声明中使用 extern"C" .然后包括该标头的任何人都将期望使用C链接标准而不是C ++装饰的形式针对它进行链接.如果包含了 warplib.h ，则 warplib.cpp 源文件和后续的目标文件将正确公开函数 foo .

You should only need extern "C" on the declaration. Anyone then including that header will expect to link against it using the C linking standard, rather than the C++ decorated form. The warplib.cpp source file, and subsequent object file will expose the function foo correctly if warplib.h is included.

使用MSVC时，有大量半有用的脚本，并提供了构建环境"控制台快捷方式，并提供了许多与开发相关的环境变量和路径.我建议找到合适的脚本来执行，以将这些变量插入您的环境中，或运行开发控制台.

When using MSVC, there are a plethora of semi-useful scripts, and "build environment" console shortcuts provided, with a lot of dev-related environment variables and paths provided. I recommend locating a suitable script to execute to insert these variables into your environment, or running the dev console.

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