linux/if.h 和 net/if.h 有什么问题？
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What's wrong with linux/if.h and net/if.h?
提问by u1105178
In my project, I include pfring.h, but compile error: some functions in net/if.h and linux/if.h are redefinition. I found that the pfring.h include linux/if.h So, I test a program, my test code:
在我的项目中，我包含了pfring.h，但是编译错误：net/if.h 和linux/if.h 中的一些函数被重新定义。我发现 pfring.h 包含 linux/if.h 所以，我测试了一个程序，我的测试代码：
#include <linux/if.h>
#include <net/if.h>
int main(void) {
return 0;
}
It expected compile error. So, what's wrong with linux/if.h and net/if.h ? Can not I include them at once?
它预计编译错误。那么， linux/if.h 和 net/if.h 有什么问题？我不能一次包括它们吗？
error message:
错误信息：
In file included from test.c:1:0:
/usr/include/linux/if.h:178:19: error: field 'ifru_addr' has incomplete type
/usr/include/linux/if.h:179:19: error: field 'ifru_dstaddr' has incomplete type
/usr/include/linux/if.h:180:19: error: field 'ifru_broadaddr' has incomplete type
/usr/include/linux/if.h:181:19: error: field 'ifru_netmask' has incomplete type
/usr/include/linux/if.h:182:20: error: field 'ifru_hwaddr' has incomplete type
In file included from test.c:2:0:
/usr/include/net/if.h:45:5: error: expected identifier before numeric constant
/usr/include/net/if.h:112:8: error: redefinition of 'struct ifmap'
/usr/include/linux/if.h:136:8: note: originally defined here
/usr/include/net/if.h:127:8: error: redefinition of 'struct ifreq'
/usr/include/linux/if.h:170:8: note: originally defined here
/usr/include/net/if.h:177:8: error: redefinition of 'struct ifconf'
/usr/include/linux/if.h:219:8: note: originally defined here
采纳答案by u1105178
This problem has been resolved, add the compile flag -DHAVE_PCAP is fix. ;-)
此问题已解决，添加编译标志 -DHAVE_PCAP 已修复。;-)
回答by Dmitry
For me (on Ubuntu 12.04 x64) the following include solved the problem:
对我来说（在 Ubuntu 12.04 x64 上）以下包括解决了这个问题：
#include <sys/socket.h> // <-- This one
#include <linux/if.h>
#include <linux/if_tun.h>
回答by A. Binzxxxxxx
At first let us talk about the source: The header files are from different Packages as you can see asking dpkg.
首先让我们谈谈来源：头文件来自不同的包，你可以看到询问dpkg.
$ dpkg -S /usr/include/linux/if.h
linux-libc-dev:i386: /usr/include/linux/if.h
$ dpkg -S /usr/include/net/if.h
libc6-dev:i386: /usr/include/net/if.h
linux-libc-devis part of linux kernel packages while libc6-devis part of the libc6(Standard C library in version 6).
linux-libc-dev是 linux 内核包libc6-dev的一部分，同时是libc6（版本 6 中的标准 C 库）的一部分。
It seams like they are interchangeable so you should only use one (not 100% sure about this). If you pick linux/if.h, you may depend on Kernel versions with your compiled binary.
看起来它们是可以互换的，所以你应该只使用一个（不是 100% 确定）。如果你选择linux/if.h，你可能依赖于你编译的二进制文件的内核版本。
All new Library versions I have in mind stick with net/if.hinstead of the linux one - so you should do the same.
我想到的所有新库版本都坚持使用net/if.h而不是 linux 版本 - 所以你应该这样做。
回答by user31986
If you are using one of the interface state flags (eg: IFF_UP, etc.), you need one more header than mentioned in other posts.
如果您正在使用接口状态标志之一（例如：IFF_UP 等），您需要一个比其他帖子中提到的更多的标头。
#include <sys/types.h> // <==
#include <sys/socket.h>
#include <linux/if.h>
