IoGetFunctionCodeFromCtlCode macro (wdm.h)

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

Syntax

void IoGetFunctionCodeFromCtlCode(
  [in] ControlCode
);

Parameters

[in] ControlCode

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

None

Remarks

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

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

Requirements

Requirement	Value
Minimum supported client	Available starting with Windows 2000.
Target Platform	Desktop
Header	wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
IRQL	Any level

See also

IoBuildDeviceIoControlRequest