关于流驱动XXX_Init()、XXX_Open()函数的返回值

sofy231

关于流驱动XXX_Init()、XXX_Open()函数的返回值 [复制链接]

流驱动接口函数
DWORD XXX_Init( DWORD dwContext);
DWORD XXX_Open(DWORD hDeviceContext, DWORD AccessCode, DWORD ShareMode);

这两个函数的返回值各表示什么意思？他们的返回值是一样的吗？
我只知道参数hDeviceContext应该是Init函数的返回值。

望达人指点

yanshen

看PB帮助

This function opens a device for reading, writing, or both. An application indirectly invokes this function when it calls the CreateFile function to open special device file names.

DWORD XXX_Open(
  DWORD hDeviceContext,
  DWORD AccessCode,
  DWORD ShareMode
);
Parameters
hDeviceContext
[in] Handle to the device context. The XXX_Init (Device Manager) function creates and returns this handle.
AccessCode
[in] Access code for the device. The access is a combination of read and write access from CreateFile.
ShareMode
[in] File share mode of the device. The share mode is a combination of read and write access sharing from CreateFile.
Return Values
This function returns a handle that identifies the open context of the device to the calling application. If your device can be opened multiple times, use this handle to identify each open context. This identifier is passed into the XXX_Read (Device Manager), XXX_Write (Device Manager), XXX_Seek (Device Manager), and XXX_IOControl (Device Manager) functions. This function returns zero if the device cannot be opened.

Remarks
When this function executes, your device should allocate the resources that it needs for each open context and prepare for operation. This might involve preparing the device for reading or writing and initializing data structures it uses for operation.

Device Manager uses the XXX prefix. When implementing the stream interface, replace XXX with a prefix appropriate for your implementation or use undecorated entry point names in conjunction with DEVFLAGS_NAKEDENTRIES. For more information about other valid Flags values, see ActivateDeviceEx

lmx5078

学习了！！！

之城

DWORD XXX_Init(DWORD dwContext)
参数：指向一个描述设备接口的字符串，通常为流接口驱动在注册表中的对应项        下的Prefix值
返回值：若调用成功，返回一个驱动程序句柄
描述：当用户开始使用设备的时候，例如PC卡初始化时，设备管理器调用这个函数来初始化PC卡设备，这个函数并不是由应用程序直接调用的，而是通过函数执行的，若成功返回一个句柄，该句柄也是XXX_Open()函数入库参数? hDeviceContext 的取值???

DWORD XXX_Open(DWORD hDeviceContext, DWORD AccessCode, DWORD ShareMode)：??????
?参数： hDeviceContext：设备驱动的句柄，在XXX_Init调用时返回的
????????????? AccessCode：访问权限代码，一般是只读或者只写或者读写
????????????? ShareMode：共享模式，是否支持共享或者独享这个参数用于一些特殊设备，例如一些PC卡的设                         备读或写的时候是否共享
返回值：返回驱动程序的句柄
描述：这个函数用于打开一个设备驱动程序，当应用程序准备对某个设备进行读或写操作的时候，必须先          执行CreateFile()函数