用外部“C”包装C库除了内部C ++包括 [英] Wrapping a C lib with extern "C" except an internal C++ include

问题描述

我有一个C库，我需要在C ++代码中使用，所以我需要包装整个lib与 externC块。问题是，库似乎包含一个C ++编译的代码，所以包装整个lib也会包装该C ++头。

I have a C library that I need to use in a C++ code, so I need to wrap the whole lib with an extern "C" block. The problem is that the library seems to include a C++ compiled code, so wrapping the whole lib would also wrap that C++ header.

内部 lib.h 我只包含我想要公开的所有内部标头，例如：

Inside lib.h I only include all the internal headers I want to expose, something like this:

#ifndef LIB_H
#define LIB_H

#include "lib_foo.h"
#include "lib_bar.h"
#include "lib_baz.h"

#endif

<使用lib。

So the client will only need to include lib.h to use the lib.

在我的第一次尝试中，我做到了：

In my first attempt I've done this:

#ifndef LIB_H
#define LIB_H

extern "C" {
  #include "lib_foo.h"
  #include "lib_bar.h"
  #include "lib_baz.h"
}

#endif

$ b b

但是，当我在 already_compiled_c ++。h 中执行任何函数时，我会收到符号查找错误。

But then I get a symbol lookup error when I execute any function inside already_compiled_c++.h.

如何避免在 already_compiled_c ++。h 头文件中应用 externC？

How can I avoid from applying extern "C" in the already_compiled_c++.h header file?

编辑：

这不是一个问题使用 externC，这是一个问题链接编译的c ++库与gyp正确：

Solved. This was not a problem using extern "C", it was a problem linking the compiled c++ library with gyp correctly: Using shared library in Gyp in node-sqlite3

推荐答案

请注意， extern C 不是合法的C，所以它必须只包括编译为C ++。

Note that extern C isn't legal C, so it must only be included hen compiling as C++.

already_compiled_c ++。h标头可能包含多个包含的警告，因此只需先包含它：

The already_compiled_c++.h header probably contains a guard against multiple includes, so just include it first:

#ifndef LIB_H
#define LIB_H

# This include added so that it won't get marked extern "C" when included by lob_foo.h.
#include <already_compiled_c++.h>

#ifdef __cplusplus
extern "C" {
#endif

  #include "lib_foo.h"
  #include "lib_bar.h"
  #include "lib_baz.h"

#ifdef __cplusplus
}
#endif

#endif

注意：您需要检查 already_compiled_c ++。h 并添加相应的条件。

Note: You need to check if already_compiled_c++.h is conditionally included and add the corresponding conditionals.

这篇关于用外部“C”包装C库除了内部C ++包括的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！