CTL_CODE

  • Article

This macro is used to create a unique system I/O control code (IOCTL).

CTL_CODE(
  DeviceType,
  Function,
  Method,
  Access
);

Parameters

  • DeviceType
    Defines the type of device for the given IOCTL. This parameter can be no bigger then a WORD value. The values used by Microsoft are in the range 0-32767 and the values 32768-65535 are reserved for use by OEMs and IHVs. The following list shows the device types defined by the system:

    • FILE_DEVICE_BEEP
    • FILE_DEVICE_CD_ROM
    • FILE_DEVICE_CD_ROM_FILE_SYSTEM
    • FILE_DEVICE_CONTROLLER
    • FILE_DEVICE_DATALINK
    • FILE_DEVICE_DFS
    • FILE_DEVICE_DISK
    • FILE_DEVICE_DISK_FILE_SYSTEM
    • FILE_DEVICE_FILE_SYSTEM
    • FILE_DEVICE_INPORT_PORT
    • FILE_DEVICE_KEYBOARD
    • FILE_DEVICE_MAILSLOT
    • FILE_DEVICE_MIDI_IN
    • FILE_DEVICE_MIDI_OUT
    • FILE_DEVICE_MOUSE
    • FILE_DEVICE_MULTI_UNC_PROVIDER
    • FILE_DEVICE_NAMED_PIPE
    • FILE_DEVICE_NETWORK
    • FILE_DEVICE_NETWORK_BROWSER
    • FILE_DEVICE_NETWORK_FILE_SYSTEM
    • FILE_DEVICE_NULL
    • FILE_DEVICE_PARALLEL_PORT
    • FILE_DEVICE_PHYSICAL_NETCARD
    • FILE_DEVICE_PRINTER
    • FILE_DEVICE_SCANNER
    • FILE_DEVICE_SERIAL_MOUSE_PORT
    • FILE_DEVICE_SERIAL_PORT
    • FILE_DEVICE_SCREEN
    • FILE_DEVICE_SOUND
    • FILE_DEVICE_DEVICE_STREAMS
    • FILE_DEVICE_TAPE
    • FILE_DEVICE_TAPE_FILE_SYSTEM
    • FILE_DEVICE_TRANSPORT
    • FILE_DEVICE_UNKNOWN
    • FILE_DEVICE_VIDEO
    • FILE_DEVICE_VIRTUAL_DISK
    • FILE_DEVICE_WAVE_IN
    • FILE_DEVICE_WAVE_OUT
    • FILE_DEVICE_8042_PORT
    • FILE_DEVICE_NETWORK_REDIRECTOR
    • FILE_DEVICE_BATTERY
    • FILE_DEVICE_BUS_EXTENDER
    • FILE_DEVICE_MODEM
    • FILE_DEVICE_VDM
    • FILE_DEVICE_MASS_STORAGE
    • FILE_DEVICE_SMB
    • FILE_DEVICE_KS
    • FILE_DEVICE_CHANGER
    • FILE_DEVICE_SMARTCARD
    • FILE_DEVICE_ACPI
    • FILE_DEVICE_DVD
    • FILE_DEVICE_FULLSCREEN_VIDEO
    • FILE_DEVICE_DFS_FILE_SYSTEM
    • FILE_DEVICE_DFS_VOLUME

    The following list shows device types specific to Windows CE:

    • FILE_DEVICE_HAL
    • FILE_DEVICE_CONSOLE
    • FILE_DEVICE_PSL
    • FILE_DEVICE_SERVICE

  • Function
    Defines an action within the device category. That function codes 0-2047 are reserved for Microsoft, and 2048-4095 are reserved for OEMs and IHVs. The function code can be no larger then 4095.

  • Method
    Defines the method codes for how buffers are passed for I/O and file system controls. The following list shows the possible values for this parameter:

    • METHOD_BUFFERED
    • METHOD_IN_DIRECT
    • METHOD_OUT_DIRECT
    • METHOD_NEITHER

    This field is ignored under Windows CE and you should always use the METHOD_BUFFERED value unless compatibility with the desktop is required using a different Method value.

  • Access
    Defines 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.

    Flag Description
    FILE_ANY_ACCESS Request all access.
    FILE_READ_ACCESS Request read access. Can be used with FILE_WRITE_ACCESS.
    FILE_WRITE_ACCESS Request write access. Can be used with FILE_READ_ACCESS.

Return Values

None.

Remarks

The macro can be used for defining IOCTL and FSCTL function control codes. All IOCTLs must be defined this way to ensure that no overlaps occur between Microsoft and OEMs and IHVs. The following illustration shows the format of the resulting IOCTL.

Requirements

OS Versions: Windows CE .NET 4.0 and later.
Header: Windev.h

See Also

DeviceIoControl

Last updated on Wednesday, April 13, 2005

© 2005 Microsoft Corporation. All rights reserved.