C++：编译翻译单元独立性和旧winsock2.h类型重定义错误

Question

据我所知，翻译单位之间在编译阶段没有任何关系。您能解释一下为什么我会有这种奇怪的行为:在一个A.cpp中包含windows.h之后(实际上它不使用套接字api，也不包括winsock2.h)，我在编译另一个带有winsock2.hwinsock.h冲突的B.cpp时会出错。这个B.cpp一点也没有改变。提前谢谢。

编辑:这实际上是一个编译而不是链接错误。我已经将msvc编译器置于详细模式中，这里的标题包括树：

2>perfomancemeter.cpp
2>Note: including file: C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\numeric
2>Note: including file:  C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\iterator
2>Note: including file:   C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xutility
2>Note: including file:    C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\climits
2>Note: including file:     C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\yvals.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\sal.h
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtassem.h
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\vadefs.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\use_ansi.h
2>Note: including file:     C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\limits.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:    C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\utility
2>Note: including file:     C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\iosfwd
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\cstdio
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\stdio.h
2>Note: including file:        C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:        C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\swprintf.inl
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\cstring
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\string.h
2>Note: including file:        C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\cwchar
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\wchar.h
2>Note: including file:        C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:        C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\wtime.inl
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xstddef
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\cstddef
2>Note: including file:        C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\stddef.h
2>Note: including file:         C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdbg.h
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file: C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\algorithm
2>Note: including file:  C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\memory
2>Note: including file:   C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xmemory
2>Note: including file:    C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\cstdlib
2>Note: including file:     C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\stdlib.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:    C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\exception
2>Note: including file:     C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\eh.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:     C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\malloc.h
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:    C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\new
2>Note: including file: d:\repos\cbs\billing\common\perfomancemeter.h
2>Note: including file:  C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\vector
2>Note: including file:   C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\stdexcept
2>Note: including file:    C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xstring
2>Note: including file: d:\repos\cbs\billing\common\util.h
2>Note: including file:  d:\repos\cbs\billing\common\framework\include\types/types.h
2>Note: including file:  C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\string
2>Note: including file:   C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\istream
2>Note: including file:    C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\ostream
2>Note: including file:     C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\ios
2>Note: including file:      C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xlocnum
2>Note: including file:       C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\streambuf
2>Note: including file:        C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xiosbase
2>Note: including file:         C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xlocale
2>Note: including file:          C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\typeinfo
2>Note: including file:          C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xdebug
2>Note: including file:          C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xlocinfo
2>Note: including file:           C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\xlocinfo.h
2>Note: including file:            C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\ctype.h
2>Note: including file:             C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
2>Note: including file:            C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\locale.h
2>Note: including file:             C:\Program Files (x86)\Microsoft Visual Studio 8\VC\include\crtdefs.h
1>c:\program files (x86)\microsoft visual studio 8\vc\platformsdk\include\winsock2.h(112) : error C2011: 'fd_set' : 'struct' type redefinition
1>        c:\program files (x86)\microsoft visual studio 8\vc\platformsdk\include\winsock.h(54) : see declaration of 'fd_set'

我以前遇到过这个问题，并且知道#在包含windows头之前定义WIN32_LEAN_AND_MEAN。但为什么会发生在这种情况下呢？

Answer 1

H包括winsock。因此，即使您不直接包含和不使用它，它也会被包括在内。#define WIN32_LEAN_AND_MEAN解决了这个问题，因为这迫使只包含必要的标头。

可能性：

• 您已经以某种方式结束了两次包含winsock /winsock 2:尝试删除winsock直接包含并只包含windows.h
• 您已经在一个常见的头文件中添加了windows/winsock :检查包含层次结构。为了进行测试，移除常见的标头，并尝试将它们直接包含在源文件中。
• 打开预编译头了吗？试着关掉它

参考如下：http://social.msdn.microsoft.com/Forums/en/vcgeneral/thread/6177f9bc-db75-4317-9904-02ef55b527d0