救命啊，就写了个简单的COM 接口类就出现N多个错误

[tigertianx]

本人初学COM，对c++也不是很了解，只能说接触过，一直用C#开发的
就照着书写了接口类就出现N多个错误，求助大侠啊

#pragma once

class IMyUnknown
{
public:
virtual HRESULT _stdcall QueryInterface(const IID& iid, void * *ppv) = 0;
virtual ULONG _stdcall AddRef() = 0;
virtual ULONG _stdcall Release() =0;
};

错误信息：
e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2143: syntax error : missing ';' before '__stdcall'
e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2433: 'HRESULT' : 'virtual' not permitted on data declarations
e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2501: 'HRESULT' : missing storage-class or type specifiers
e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2143: syntax error : missing ',' before '&'
e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2059: syntax error : '&'
e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2253: 'QueryInterface' : pure specifier only applies to virtual function - specifier ignored
e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2143: syntax error : missing ';' before '__stdcall'
e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2433: 'ULONG' : 'virtual' not permitted on data declarations
e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2501: 'ULONG' : missing storage-class or type specifiers
e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2253: 'AddRef' : pure specifier only applies to virtual function - specifier ignored
e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2143: syntax error : missing ';' before '__stdcall'
e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2433: 'ULONG' : 'virtual' not permitted on data declarations
e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2501: 'ULONG' : missing storage-class or type specifiers
e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2253: 'Release' : pure specifier only applies to virtual function - specifier ignored

当然说白了这个3处错误都是同样的错误，但是本人愚钝就是找不出来

[SKATE11]

是不是键工程建错了

[图灵狗]

参考http://www.vckbase.com/index.php/wv/1547.html

引用 楼主 tigertianx 的回复:

本人初学COM，对c++也不是很了解，只能说接触过，一直用C#开发的 就照着书写了接口类就出现N多个错误，求助大侠啊 #pragma once class IMyUnknown { public: virtual HRESULT _stdcall QueryInterface(const IID& iid, void * *ppv) = 0; virtual ULONG _stdcall AddRef() = 0; virtual ULONG _stdcall Release() =0; }; 错误信息： e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2143: syntax error : missing ';' before '__stdcall' e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2433: 'HRESULT' : 'virtual' not permitted on data declarations e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2501: 'HRESULT' : missing storage-class or type specifiers e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2143: syntax error : missing ',' before '&' e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2059: syntax error : '&' e:\work project\test project\com\dictcomp\imyunknown.h(6) : error C2253: 'QueryInterface' : pure specifier only applies to virtual function - specifier ignored e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2143: syntax error : missing ';' before '__stdcall' e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2433: 'ULONG' : 'virtual' not permitted on data declarations e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2501: 'ULONG' : missing storage-class or type specifiers e:\work project\test project\com\dictcomp\imyunknown.h(7) : error C2253: 'AddRef' : pure specifier only applies to virtual function - specifier ignored e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2143: syntax error : missing ';' before '__stdcall' e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2433: 'ULONG' : 'virtual' not permitted on data declarations e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2501: 'ULONG' : missing storage-class or type specifiers e:\work project\test project\com\dictcomp\imyunknown.h(8) : error C2253: 'Release' : pure specifier only applies to virtual function - specifier ignored 当然说白了这个3处错误都是同样的错误，但是本人愚钝就是找不出来

[tigertianx]

我建的是DLL工程啊，编译的时候就报了很多错

[tigertianx]

谢谢啦，问题解决了，最后下了源代码，看了下 是因为没有定义接口类的标识符 typedef struct _GUID GUID; typedef GUID IID; extern "C" const IID IID_IUnknown = { 0x00000000, 0x0000, 0x0000, { 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46} } ; 引起的，不过话说回来，c++的报错有时候是和报错位置处的代码没有关系的， 而可能是因为代码不完整引起的，所以看错误信息让人摸不着头脑