error LNK2005

[IT_SW_FW]

PLAYVIDEO.obj : error LNK2005: "struct _DDSURFACEDESC ddsd" (?ddsd@@3U_DDSURFACEDESC@@A) already defined in PlayV.obj

要怎样解决？

[hdqqq]

估计你把这个变量定义到头文件了， 两个文件include这个头文件， 所以有两个全局变量存在，解决办法， 头文件中用extern声明， 在cpp文件中定义。

[fox000002]

重定义问题

解决的话，就是头文件中不要直接定义变量，仅做些声明，如

extern struct U_DDSURFACEDESC aaa;

然后在对应的 .cpp 中定义它

struct U_DDSURFACEDESC aaa;

其它需要使用这个变量的位置，要么 include 该头文件，或直接写 extern 声明

[yyunffu]

变量重复定义问题。如果头文件需要在多个地方包含，最好放进stdafx.h当中，以防重复包含。

[greatws]

把定义放在cpp文件里，只在头文件里声明

[Gavin001]

有几种可能:
1.显示重复定义,代码中有多处做了定义
2.头文件重复包含,在头文件前加上#pragma once

[IT_SW_FW]

error:
PlayV.obj : error LNK2005: "struct IMultiMediaStream * pMMStream" (?pMMStream@@3PAUIMultiMediaStream@@A) already defined in PLAYVIDEO.obj
PlayV.obj : error LNK2005: "struct IDirectDrawSurface * pPrimarySurface" (?pPrimarySurface@@3PAUIDirectDrawSurface@@A) already defined in PLAYVIDEO.obj
PlayV.obj : error LNK2005: "struct _DDSURFACEDESC ddsd" (?ddsd@@3U_DDSURFACEDESC@@A) already defined in PLAYVIDEO.obj
PlayV.obj : error LNK2005: "struct HWND__ * hPlayWnd" (?hPlayWnd@@3PAUHWND__@@A) already defined in PLAYVIDEO.obj
PlayV.obj : error LNK2005: "struct IDirectDraw * pDD" (?pDD@@3PAUIDirectDraw@@A) already defined in PLAYVIDEO.obj

Link lib顺序:
Searching Libraries
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\kernel32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\user32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\gdi32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\winspool.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\comdlg32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\advapi32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\shell32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\ole32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\oleaut32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\uuid.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\odbc32.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\odbccp32.lib:
Searching C:\mssdk\lib\ddraw.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\MSVCRT.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\OLDNAMES.lib:
Searching C:\mssdk\lib\AMSTRMID.lib:
Searching C:\Program Files\Microsoft Visual Studio\VC98\LIB\kernel32.lib:
Done Searching Libraries

PlayV.h:
#include "ddraw.h"
#include "mmstream.h"
#include "amstream.h"
#include "ddstream.h"

DDSURFACEDESC ddsd;
IDirectDraw *pDD;
IDirectDrawSurface *pPrimarySurface;
IMultiMediaStream *pMMStream;
HWND hPlayWnd;

PlayV.cpp:
#include "PlayV.h"

#pragma comment(lib, "AMSTRMID")

当#include "PlayV.h"加入PLAYVIDEO.CPP时就出错
PLAYVIDEO.CPP:
#include "stdafx.h"
#include "resource.h"
#include "PlayV.h"

我想知道哪二个.lib重复了？请问要怎样修改？

[vcPlayer]

不要在头文件定义变量。在任何一个CPP文件中定义，然后在stdafx.h 中用extern 声明。。。。

[IT_SW_FW]

所有人说的都对，用这种方法也可以解决，我就是想知道到底是哪二个.lib重用了?谢谢．

[IT_SW_FW]

老大们快点啊，我想结帖啦

[IT_SW_FW]

到底在哪重定义了？唉！想不明白，继续想．呵呵

[hdqqq]

不是lib重定义了，是两个obj中有重复，PLAYVIDEO.obj PlayV.obj ， 估计是你工程中的文件。