参考博客

​ Linux系统并没有对应的注册表和IUnknow接口，所以需要自己编写。

• 类型定义 type.h

  /*$file:		type.h$date:		2020年8月13日$author:	hehl$describe:	类型定义$other:
  */
  #ifndef __TYPE_H__
  #define __TYPE_H__typedef long HRESULT;			// 32位机为四字节，64位机为八字节，和指针的类型长度一致
  typedef unsigned long ULONG;typedef struct _GUID
  {unsigned long Data1;		// 32位 0x0000-0x0000unsigned short Data2;		// 16位 0x0000unsigned short Data3;		// 16位 0x0000unsigned char Data4[8];		// 64位	0x0000-0x0000-0x0000-0x0000
  }GUID;	// guid	128位的全局唯一标识符（Globally Unique Identifier）typedef GUID IID;#define interface struct	// 定义接口为结构体#define E_NOINTERFACE 0x80004002L	// 错误码，先不管他
  #define S_OK 0#endif
  

• 接口基类 iunknown.h

/*$file:		iunknown.h$date:		2020年8月13日$author:	hehl$describe:	接口基类$other:
*/
#ifndef __IUNKNOWN_H__
#define __IUNKNOWN_H__#include "type.h"interface IUnknown	// interface相当于struct，c语言风格
{virtual HRESULT QueryInterface(const IID& iid, void** ppv) = 0;	// 请求接口指针，相当于查询一个方法virtual ULONG AddRef() = 0;		// 增加引用计数virtual ULONG Release() = 0;	// 减少引用计数
};	// windows提供的IUnknown类的三个接口，Linux下需要自己实现，windows这里为类#endif

• GUID和接口头文件 interface.h

/*$file:		interface.h$date:		2020年8月13日$author:	hehl$describe:	接口类 + GUID$other:
*/
#ifndef __INTERFACE_H__
#define __INTERFACE_H__#include "iunknown.h"interface IX : IUnknown		// 这个总感觉怪怪的，先不管这种写法了，按照c++的写法应该是继承把?
{virtual void Fx() = 0;	// 纯虚函数，由派生类实现具体方法
};interface IY : IUnknown
{virtual void Fy() = 0;	// 纯虚函数，由派生类实现具体方法
};interface IZ : IUnknown
{virtual void Fz() = 0;	// 纯虚函数，由派生类实现具体方法
};// 8 4 4 12
// 9F153BC9-E06F-7B23-F4FC-A96B64ABA9D3
extern "C"
{const IID IID_IX = { 0x9F153BC9, 0xE06F , 0x7B23 , \{0xF4, 0xFC, 0xA9, 0x6B, 0x64, 0xAB, 0xA9, 0xD3} };const IID IID_IY = { 0x9F153BC9, 0xE06F , 0x7B23 , \{0xF4, 0xFC, 0xA9, 0x6B, 0x64, 0xAB, 0xA9, 0xD4} };const IID IID_IZ = { 0x9F153BC9, 0xE06F , 0x7B23 , \{0xF4, 0xFC, 0xA9, 0x6B, 0x64, 0xAB, 0xA9, 0xD5} };const IID IID_IUnknown = { 0x9F153BC9, 0xE06F , 0x7B23 , \{0xF4, 0xFC, 0xA9, 0x6B, 0x64, 0xAB, 0xA9, 0xD6} };
}#endif

• 组件实现文件 component.cpp

/*$file:		component.cpp$date:		2020年8月13日$author:	hehl$describe:	组件实现$other:
*/
#include <iostream>
#include "type.h"
#include "interface.h"using namespace std;bool operator==(const IID& guid1, const IID& guid2)
{if (guid1.Data1 != guid2.Data1 || guid1.Data2 != guid2.Data2 || \guid1.Data3 != guid2.Data3){return false;}for (int i = 0; i < 8; i++){if (guid1.Data4[i] != guid2.Data4[i]){return false;}}return true;
}// 额... = =、	类以后还是定义再头文件里面好点~~先不管了
class CA : public IX
{
private:// IUnknown的接口virtual HRESULT QueryInterface(const IID& iid, void** ppv);virtual ULONG AddRef();virtual ULONG Release();// IX的接口virtual void Fx();public:CA();~CA();private:long m_cRef;
};CA::CA()
{cout << "CA::CA()\n";
}CA::~CA()
{cout << "CA::~CA()\n";
}HRESULT CA::QueryInterface(const IID& iid, void** ppv)
{if (iid == IID_IX){cout << "CA::QueryInterface() to IX\n";*ppv = static_cast<IX*>(this);	// 等价于 *ppv = (IX*)this;}else if (iid == IID_IUnknown){cout << "CA::QueryInterface() to IUnknown\n";*ppv = static_cast<IUnknown*>(this);}else{cout << "CA::QueryInterface() Interface is not support\n";*ppv = NULL;return E_NOINTERFACE;}reinterpret_cast<IUnknown*>(*ppv)->AddRef();
}ULONG CA::AddRef()
{m_cRef++;cout << "CA::AddRef() m_cRef:" + m_cRef << endl;
}ULONG CA::Release()
{if (0 == (--m_cRef)){delete this;return 0;}return m_cRef;
}void CA::Fx()
{cout << "CA::Fx() called\n";
}// 由动态库指向此函数
extern "C" IUnknown * CreateInstance()
{IUnknown* pI = static_cast<IX*>(new CA);pI->AddRef();return pI;
}

• 客户端 client.cpp

/*$file:		client.cpp$date:		2020年8月13日$author:	hehl$describe:	组件实现$other:
*/
#include <iostream>
#include "interface.h"
#include "create.h"int main(int argc, char** argv)
{HRESULT hr;char name[40] = { 0 };CREATE create;cout << "Enter the file name of a component to use[lib***.so]:";cin >> name;cout << "Get an IUnknown pointer." << endl;IUnknown* pUnknown = create.CallCreateInstance(name);if (pUnknown == NULL){cout << "CallCreateInstance fail!\n";exit(1);}cout << "Get Interface IX.\n";IX* pIX = NULL;hr = pUnknown->QueryInterface(IID_IX, (void**)&pIX);if (hr < 0){cout << "Counld not get the IX interface.\n";}else{cout << "Success get the IX interface.\n";pIX->Fx();pIX->Release();}cout << "Release the IUnknown interface.\n";pUnknown->Release();create.closeHandle();return 0;}

• Makefile

objects=component.o client.o create.oall : libcmpnt clientlibcmpnt:component.og++ -shared -Wl,-soname -O3 -o libcmpnt.so component.ocmpnt.o : interface.h  iunknown.h  type.hg++ -c -fPIC component.cpp  -O3 -o component.oclient : client.o create.og++ -g -rdynamic  -Wl,--no-as-needed -ldl -o client client.o create.oclient.o :g++ -g -c client.cppcreate.o :g++ -g -c create.cpp.PYTHON : clean
clean :rm -f ${objects}

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