IoGetFunctionCodeFromCtlCode function

The IoGetFunctionCodeFromCtlCode macro returns the value of the function code contained in an I/O control code.

Syntax


ULONG IoGetFunctionCodeFromCtlCode(
  _In_ ULONG ControlCode
);

Parameters

ControlCode [in]

The IOCTL_XXX (or FSCTL_XXX) value, which can be obtained from the driver's I/O stack location of the IRP at Parameters.DeviceIoControl.IoControlCode.

Return value

IoGetFunctionCodeFromCtlCode returns the value of the Function part of the given IOCTL_XXX code.

Remarks

For information about the layout of IOCTL codes, see Using I/O Control Codes.

Requirements

Target platform

Version

Available starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

IRQL

Any level

See also

IoBuildDeviceIoControlRequest

 

 

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