使用C库不链接的gcc / g ++的 [英] C-library not linking using gcc/g++

问题描述

我有一个C库我在gcc时使用。图书馆有扩展的.lib，但总是连在一起作为静态库。如果我写它使用库作为C- code，一切，都OK的程序。如果我不过文件重命名为.CPP（做简单的东西，在这两个C / C ++工程）我得到了一个未定义的参考。这些都是简单的小程序我写的用于测试目的所以没有花哨的东西。我编译使用：

I have a c-library which I use in gcc. The library has the extension .lib but is always linked as a static library. If i write a program which uses the library as c-code, everything as a-ok. If I however rename the file to .cpp (doing simple stuff that works in both c/c++) I get undefined reference. These are simple small programs I write for testing purposes so no fancy stuff. I compile using:

gcc -g -Wall -I <path to custom headers> -o program main.c customlibrary.lib -lm -lpthread

以上的作品就像一个魅力。但是：

The above works like a charm. However:

g++ -g -Wall -I <path to custom headers> -o program main.cpp customlibrary.lib -lm -lpthread

或

gcc -g -Wall -I <path to custom headers> -o program main.cpp customlibrary.lib -lm -lpthread -lstdc++

结果不确定的参考customlibrary.lib任何功能。我试图创建符号链接名为customlibrary.a但没有运气。

results in undefined reference to any function in customlibrary.lib. I tried creating a symbolic link named customlibrary.a but no luck.

任何想法将大大appriciated。为什么不会g ++的发现识别我的图书馆。不幸的是我没有访问库的源$ C ​​$ C，但链接一个C-lib添加到C ++应该不会有问题吧？

Any ideas would be much appriciated. Why won't g++ find recognize my library. Unfortunately I have no access to the source code of the libraries but linking a c-lib to c++ should not be a problem right?

推荐答案

您库中似乎有假定它会从C，而不是C ++调用的API。这是重要的，因为C ++有效地需要从库导出的符号，在他们不仅仅是函数名的更多信息。这是由名称重整的功能来处理。

Your library appears to have an API that assumes it will be called from C, not C++. This is important because C++ effectively requires that the symbols exported from a library have more information in them than just the function name. This is handled by "name mangling" the functions.

我假设你的库有一个声明公共接口包含文件。为了使其与C和C ++兼容，您应该安排告诉C ++编译器，它声明的职能应假定用C的联动和命名。

I assume your library has an include file that declares its public interface. To make it compatible with both C and C++, you should arrange to tell a C++ compiler that the functions it declares should be assumed to use C's linkage and naming.

一个可能简单的答案来测试，这是要做到这一点：

A likely easy answer to test this is to do this:

extern "C" {
#include "customlibrary.h"
}

在main.cpp中，而不是仅仅包括 customlibrary.h 直接。

为了让自己在两种语言工作，正确声明其功能类似于C和C ++的头，把附近的头文件的顶部以下内容：

To make the header itself work in both languages and correctly declare its functions as C-like to C++, put the following near the top of the header file:

#ifdef __cplusplus
extern "C" {
#endif

和底部附近的以下内容：

and the following near the bottom:

#ifdef __cplusplus
}
#endif

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