国内卡一卡二卡三网站视频,自己建设的网站怎么赚钱,怎么做免费的网站,网站建设属于哪种公司我们在说DeviceIoControl函数时其第二个参数dwIoControlCode就是由CTL_CODE宏定义的#xff0c;下边我们可以了解一下CTL_CODE的内容。CTL_CODE#xff1a;用于创建一个唯一的32位系统I/O控制代码#xff0c;这个控制代码包括4部分组成#xff1a;DeviceType#xff08;设…我们在说DeviceIoControl函数时其第二个参数dwIoControlCode就是由CTL_CODE宏定义的下边我们可以了解一下CTL_CODE的内容。CTL_CODE用于创建一个唯一的32位系统I/O控制代码这个控制代码包括4部分组成DeviceType设备类型高16位16-31位Access访问限制14-15位Function功能2-13位MethodI/O访问内存使用方式。 This macro creates a unique system I/O control code (IOCTL). #define CTL_CODE(DeviceType, Function, Method, Access) (((DeviceType) 16) | ((Access) 14) | ((Function) 2) | (Method)
) Parameters参数 DeviceTypeDefines the type of device for the given IOCTL. This parameter can be no bigger than a WORD value. The values used by Microsoft are in the range 0-32767; the values 32768-65535 are reserved for use by OEMs and IHVs. The following device types are defined by the system: FILE_DEVICE_BEEPFILE_DEVICE_CD_ROMFILE_DEVICE_CD_ROM_FILE_SYSTEMFILE_DEVICE_CONTROLLERFILE_DEVICE_DATALINKFILE_DEVICE_DFSFILE_DEVICE_DISKFILE_DEVICE_DISK_FILE_SYSTEMFILE_DEVICE_FILE_SYSTEMFILE_DEVICE_INPORT_PORTFILE_DEVICE_KEYBOARDFILE_DEVICE_MAILSLOTFILE_DEVICE_MIDI_INFILE_DEVICE_MIDI_OUTFILE_DEVICE_MOUSEFILE_DEVICE_MULTI_UNC_PROVIDERFILE_DEVICE_NAMED_PIPEFILE_DEVICE_NETWORKFILE_DEVICE_NETWORK_BROWSERFILE_DEVICE_NETWORK_FILE_SYSTEMFILE_DEVICE_NULLFILE_DEVICE_PARALLEL_PORTFILE_DEVICE_PHYSICAL_NETCARDFILE_DEVICE_PRINTERFILE_DEVICE_SCANNERFILE_DEVICE_SERIAL_MOUSE_PORTFILE_DEVICE_SERIAL_PORTFILE_DEVICE_SCREENFILE_DEVICE_SOUNDFILE_DEVICE_DEVICE_STREAMSFILE_DEVICE_TAPEFILE_DEVICE_TAPE_FILE_SYSTEMFILE_DEVICE_TRANSPORTFILE_DEVICE_UNKNOWNFILE_DEVICE_VIDEOFILE_DEVICE_VIRTUAL_DISKFILE_DEVICE_WAVE_INFILE_DEVICE_WAVE_OUTFILE_DEVICE_8042_PORTFILE_DEVICE_NETWORK_REDIRECTORFILE_DEVICE_BATTERYFILE_DEVICE_BUS_EXTENDERFILE_DEVICE_MODEMFILE_DEVICE_VDMFILE_DEVICE_MASS_STORAGEFILE_DEVICE_SMBFILE_DEVICE_KSFILE_DEVICE_CHANGERFILE_DEVICE_SMARTCARDFILE_DEVICE_ACPIFILE_DEVICE_DVDFILE_DEVICE_FULLSCREEN_VIDEOFILE_DEVICE_DFS_FILE_SYSTEMFILE_DEVICE_DFS_VOLUME The following device types are specific to Windows CE: FILE_DEVICE_HALFILE_DEVICE_CONSOLEFILE_DEVICE_PSLFILE_DEVICE_SERVICE FunctionDefines an action within the device category. Function codes 0-2047 are reserved for Microsoft; codes 2048-4095 are reserved for OEMs and IHVs. A function code can be no larger then 4095. MethodDefines the method codes for how buffers are passed for I/O and file system controls. The following values are possible for this parameter: METHOD_BUFFEREDMETHOD_IN_DIRECTMETHOD_OUT_DIRECTMETHOD_NEITHER This field is ignored by Windows CE. You should always use the METHOD_BUFFERED value unless compatibility with Windows-based desktop platforms is required using a different Method value. AccessDefines the access check value for any access. The following table shows the possible flags for this parameter. The FILE_ACCESS_ANY is generally the correct value. FlagDescriptionFILE_ANY_ACCESSRequest all access.FILE_READ_ACCESSRequest read access. Can be used with FILE_WRITE_ACCESS.FILE_WRITE_ACCESSRequest write access. Can be used with FILE_READ_ACCESS. Return Values返回值 None. Remarks备注 The macro can be used for defining IOCTL and FSCTL function control codes. All IOCTLs must be defined this way to ensure that values used by Microsoft, OEMs, and IHVs do not overlap. The following illustration shows the format of the resulting IOCTL. 举例说明一下 我定义两个IOCTL,一个用于对设备的读一个用于对设备的写 #define ATST2004_IOCTL_READ CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_BUFFERED, FILE_READ_DATA) #define ATST2004_IOCTL_WRITE CTL_CODE(FILE_DEVICE_UNKNOWN, 0x801, METHOD_BUFFERED, FILE_WRITE_DATA) 在VC中使用不需要进行处理假如我要在VB中使用这两个IOCTL就需要进行查值计算了计算后定义如下 Private Const ATST2004_IOCTL_READ H226000 Private Const ATST2004_IOCTL_WRITE H22A004 关于MethodI/O访问内存使用方式我们下篇在说。
