纠结！急求教一下"error LNK2005: "public: virtual __cdecl CUnknown::~CUnknown(void)""的问题

[ayiyi0910]

我最近在molie上用driectshow对视频进行处理，但问题一直不段．下面是我写了一个简单的继承CTransformFilter类，但编译的时候一直出错

环境vs2008, windows mobile 6(vs2005和windows mobile也会出问题同样的错误)

1 .h
#pragma once

#include "streams.h"

class CDSGrabber : public CTransformFilter
{
public:
CDSGrabber(TCHAR *, LPUNKNOWN, REFCLSID clsid);

~CDSGrabber(void);
};

2 .cpp
#include "StdAfx.h"
#include "DSGrabber.h"


CDSGrabber::CDSGrabber(TCHAR *pName, LPUNKNOWN pUnk, REFCLSID clsid)
: CTransformFilter(pName, pUnk, clsid)
{
}

CDSGrabber::~CDSGrabber(void)
{
}

3 link lib
strmbase.lib
strmiids.lib

4 错误
1>uafxcw.lib(wcefont.obj) : error LNK2005: "public: virtual __cdecl CUnknown::~CUnknown(void)" (??1CUnknown@@UAA@XZ) already defined in strmbase.lib(amfilter.obj)
1>DSGrabber.obj : error LNK2019: unresolved external symbol "public: __cdecl CTransformFilter::CTransformFilter(wchar_t *,struct IUnknown *,struct _GUID const &)" (??0CTransformFilter@@QAA@PA_WPAUIUnknown@@ABU_GUID@@@Z) referenced in function "public: __cdecl CDSGrabber::CDSGrabber(wchar_t *,struct IUnknown *,struct _GUID const &)" (??0CDSGrabber@@QAA@PA_WPAUIUnknown@@ABU_GUID@@@Z)
1>DSGrabber.obj : error LNK2001: unresolved external symbol "public: virtual long __cdecl CTransformFilter::FindPin(wchar_t const *,struct IPin * *)" (?FindPin@CTransformFilter@@UAAJPB_WPAPAUIPin@@@Z)
1>DSGrabber.obj : error LNK2001: unresolved external symbol "public: virtual long __cdecl CBaseFilter::JoinFilterGraph(struct IFilterGraph *,wchar_t const *)" (?JoinFilterGraph@CBaseFilter@@UAAJPAUIFilterGraph@@PB_W@Z)
1>DSGrabber.obj : error LNK2001: unresolved external symbol "public: virtual long __cdecl CBaseFilter::QueryVendorInfo(wchar_t * *)" (?QueryVendorInfo@CBaseFilter@@UAAJPAPA_W@Z)
1>Windows Mobile 6 Professional SDK (ARMV4I)\Release\VCInterPhone.exe : fatal error LNK1120: 4 unresolved externals

[wqbyangtzeu]

关于你所描述的几个问题这里有解决方案：
http://apps.hi.baidu.com/share/detail/16803015

你自己编写的转换filter必须实现以下几个纯虚函数接口：
CheckInputType
CheckTransform
DecideBufferSize
GetMediaType

记得散分哦！

[ayiyi0910]

第一个是CUnknown::~CUnknown在基类里重复定义了

我在linker->Ignore specific libray中试过把uafxcw.lib或者strmbase.lib忽略，但是这样不行的会报更多的错，两个lib都是不能忽略的

[ayiyi0910]

后面的这个问题是宽字节的问题.
出在找到的处理方法是Congfiguration Properties->c/c++->Language里把Treat wchar_t as Built-in Type 的值从"Yes"改成"No (/Zc:wchar_t-)"，但是又会出现下面的错误
1>uafxcw.lib(wcefont.obj) : error LNK2005: "public: virtual __cdecl CUnknown::~CUnknown(void)" (??1CUnknown@@UAA@XZ) already defined in strmbase.lib(amfilter.obj)
1>Windows Mobile 6 Professional SDK (ARMV4I)\Release\VCInterPhone.exe : fatal error LNK1169: one or more multiply defined symbols found
1>Build log was saved at "file://e:\code\project\VCInterPhone\VCInterPhone\Windows Mobile 6 Professional SDK (ARMV4I)\Release\BuildLog.htm"
1>VCInterPhone - 2 error(s), 0 warning(s)

唉，急向各们求救呀，这个问题已经困扰我好几天了

[ayiyi0910]

谢谢楼上的，你给的那个链接的方法我早就实过了，但是还是不行的

我现在这４个纯虚函数接口也简单的实现了，但是出现这个的错误
1>strmbase.lib(amfilter.obj) : error LNK2005: "public: virtual __cdecl CUnknown::~CUnknown(void)" (??1CUnknown@@UAA@XZ) already defined in uafxcwd.lib(wcefont.obj)
1>Windows Mobile 6 Professional SDK (ARMV4I)\Debug\VCInterPhone.exe : fatal error LNK1169: one or more multiply defined symbols found

[ayiyi0910]

唉，被这个问题弄的头大了

[wqbyangtzeu]

我确认你的问题是环境配置有问题，你如果愿意的话可以把代码打包发给我，我帮你测试下

[ayiyi0910]

谢谢，我的代码就是我发出来的这些。我就是很简单的继承了一下CTransformFilter

[ayiyi0910]

我打包后怎么发给你呀。

[ayiyi0910]

我现在在win32下是能用的， 但是使用mfc就还有这个错误

[zhaofifan]

楼主解决没 了，我也碰到这样的问题

[依然做自己的软件]

也许还有一点是：
改调用约定为__stdcall

今天我也遇到类似的问题了， 总是提示：
无法从“CUnknown *(__cdecl *)(LPUNKNOWN,HRESULT *)”转换为“LPFNNewCOMObject”

后来在微软官网上找到了答案：
Building DirectShow Filters
http://technet.microsoft.com/zh-cn/library/aa451221

用Directshow就是要注意这些！！！