Detailed description of function parameters of the wince stream Driver Interface

DWORD xxx_init (DWORD dwcontext,

Lpcvoid lpvbuscontext );

Dwcontext: pointer to the Registry, indicating the path of the streaming activity key.

Lpvbuscontext: Used as the fourth parameter of activedevice to pass the pointer of process ing.

Returned value: If this function is successfully executed, a device context handle is returned. Otherwise, 0 is returned. This handle will be transferred to the xxx_open, xxx_powerdown, xxx_powerup, and xxx_deinit functions.

Note: This function is called when the driver is loaded by the system.

 

Bool xxx_deinit (DWORD hdevicecontext );

Hdevicecontext: The device context handle created and returned by xxx_init.

Returned value: if the call is successful, true is returned. If the call fails, false is returned.

Note: This function is called when the driver is uninstalled by the system.

 

DWORD xxx_open (DWORD hdevicecontext,

DWORD accesscode,

DWORD merge mode );

Hdevicecontext: The device context handle created and returned by xxx_init.

Accesscode: indicates the access permission of the device. The access permission is a combination of read and write permissions passed in by creatfile.

File Sharing Mode: indicates the file sharing mode of the device. The sharing mode is a combination of the Sharing permissions passed in by creatfile.

Returned value: If this function is successfully executed, a device context handle that identifies the enabled device is returned. Otherwise, 0 is returned. This handle is sent to xxx_read, xxx_write, xxx_seek, and xxx_iocontrol.

Note: This function is called when an application calls the creatfile () function.

 

Bool xxx_close (DWORD hopencontext );

Hopencontext: The device context handle created and returned by xxx_open.

Returned value: if the call is successful, true is returned. If the call fails, false is returned.

Note: This function is called when the application calls the closehandle () function.

 

DWORD xxx_read (DWORD hopencontext,

Lpvoid pbuffer,

DWORD count );

Hopencontext: The device context handle created and returned by xxx_open.

Pbuffer: pointer to the data buffer read by the device.

Count: the number of bytes that the application wants to read from the device to the buffer zone.

Returned value: "0" indicates that the end of the file has been reached, and "-1" indicates that an error has been returned. If execution is successful, the actual number of bytes is returned.

Note: This function is called when an application calls the readfile () function.

 

DWORD xxx_write (DWORD hopencontext,

Lpvoid pbuffer,

DWORD count );

Hopencontext: The device context handle created and returned by xxx_open.

Pbuffer: pointer to the data buffer to be written to the device.

Count: the number of bytes that the application wants to write to the device buffer.

Returned value: "-1" indicates an error. If execution is successful, the actual number of bytes written is returned.

Note: This function is called when an application calls the writefile () function.

 

DWORD xxx_iocontrol (DWORD hopencontext,

DWORD dwcode,

Pbyte pbufin,

DWORD dwlenin,

Pbyte pbufout,

DWORD dwlenout,

Pdword pdwactualout );

Hopencontext: The device context handle created and returned by xxx_open.

Dwcode: indicates the control operation code of I/O. These encodings are generally customized and generally included in header files.

Pbufin: pointer to the input buffer.

Dwlenin: number of bytes to be written.

Pbufout: output buffer pointer.

Dwlenout: Number of output bytes.

Pdwactualout: number of bytes actually output.

Return Value: if the call is successful, true is returned. Otherwise, false is returned ..

Note: This function is called when the application calls the deviceiocontrol () function.

 

Void xxx_powerdown (DWORD hdevicecontext );

Hdevicecontext: The device context handle created and returned by xxx_init.

Note: When the system stops supplying power to the device or calls the deviceiocontrol () function, this function is called when the I/O command is ioctl_power_xxx.

 

Void xxx_powerup (DWORD hdevicecontext );

Hdevicecontext: The device context handle created and returned by xxx_init.

Note: This function is called when the system restores power to the device, or when the deviceiocontrol () function is called, the I/O command word is ioctl_power_xxx.

 

DWORD xxx_seek (DWORD dwopen, long ldelta, word wtype );