get wdk

get wdk from http://www.microsoft.com/whdc/devtools/wdk/WDKpkg.mspx

the latest wdk now is wdk 7.0.0

I get GRMWDK_EN_7600.ISO

note:

After installing WDK in one machine , you can build driver for different version of windows & different CPU

memory management

allocate object:

CoTaskMemAlloc

free object:

CoTaskMemFree

macro for interface method

STDMETHOD:

for method definition, return type must be HRESULT

STDMETHOD_(type)

for method definition, return type is not HRESULT

STDMETHODIMP:

for method implementation, return type must be HRESULT

STDMETHODIMP_(type):

for method implementation, return type is not HRESULT

MIDL

define interface example:

[ object,

uuid(FC3B3F61-BCEC-11D1-91FE-E1CBED988F66)

]

interface IStack : IUnknown

{

import "unknwn.idl";

HRESULT Push([in] long value);

HRESULT Pop([out, retval] long* pVal);

HRESULT Empty([out, retval] boolean* pVal);

};

the mapping c++ code:

#include "wtypes.h"

/* {FC3B3F61-BCEC-11D1-91FE-E1CBED988F66} */

DEFINE_GUID(IID_IStack,

0xFC3B3F61, 0xBCEC, 0x11D1, 0x91, 0xFE,

0xE1, 0xCB, 0xED, 0x98, 0x8F, 0x66);

class IStack : public IUnknown {

public:

virtual HRESULT Push(long value) = 0;

virtual HRESULT Pop(long* value) = 0;

virtual HRESULT Empty(long* flag) = 0;

};

or

#include "wtypes.h"

/* {FC3B3F61-BCEC-11D1-91FE-E1CBED988F66} */

DEFINE_GUID(IID_IStack,

0xFC3B3F61, 0xBCEC, 0x11D1, 0x91, 0xFE,

0xE1, 0xCB, 0xED, 0x98, 0x8F, 0x66);

DECLARE_INTERFACE_(IStack, IUnknown)

{

// *** IStack methods *** //

STDMETHOD(Push) (THIS_ long value) PURE;

STDMETHOD(Pop) (THIS_ long* value) PURE;

STDMETHOD(Empty) (THIS_ long* flag) PURE;

};

interface and class of com

A COM interface is a set of related methods that have a well-defined contract but have no implementation. A COM class implements one or more interfaces, and all the services a COM class exports are defined by the interfaces it implements. Callers access the services of a COM object by calling the methods defined by its interfaces.

an interface is an abstract class that defines a set of public, pure virtual functions and contains no data members.

ex:

class IUnknown {

public:

virtual HRESULT QueryInterface(REFIID riid, void** ppv) = 0;

virtual unsigned long AddRef() = 0;

virtual unsigned long Release()= 0;

};

com

language transparency

location transparency

use MIDL(microsoft interface definition language) to define method of com interface

unique naming of class & interface: GUID

binary object model:

defines how objects are laid out in memory (hence binary). This permits any programming language or any development tool to create a COM object as long as it is capable of laying out the memory in a manner that conforms with the COM specification and calling the appropriate COM routines.

IUnknown

root of all com interface

ex:

[object, uuid(DA4A270-AIBA-lldO-BC2C-OOBOC73925BA)]

interface ITest : IUnknown {

import "unknwn.idl" // bring in definition of IUnknown

HRESULT test(void);

}