#ifndef _NTIOAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
NtFsControlFile(
    _In_ HANDLE FileHandle,
    _In_opt_ HANDLE Event,
    _In_opt_ PIO_APC_ROUTINE ApcRoutine,
    _In_opt_ PVOID ApcContext,
    _Out_ PIO_STATUS_BLOCK IoStatusBlock,
    _In_ ULONG FsControlCode,
    _In_reads_bytes_opt_(InputBufferLength) PVOID InputBuffer,
    _In_ ULONG InputBufferLength,
    _Out_writes_bytes_opt_(OutputBufferLength) PVOID OutputBuffer,
    _In_ ULONG OutputBufferLength
    );

#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwFsControlFile(
    _In_ HANDLE FileHandle,
    _In_opt_ HANDLE Event,
    _In_opt_ PIO_APC_ROUTINE ApcRoutine,
    _In_opt_ PVOID ApcContext,
    _Out_ PIO_STATUS_BLOCK IoStatusBlock,
    _In_ ULONG FsControlCode,
    _In_reads_bytes_opt_(InputBufferLength) PVOID InputBuffer,
    _In_ ULONG InputBufferLength,
    _Out_writes_bytes_opt_(OutputBufferLength) PVOID OutputBuffer,
    _In_ ULONG OutputBufferLength
    );

#endif
View code on GitHub

This function is documented in Windows Driver Kit here and here.

Function NtFsControlFile sends FSCTL_* code to File System Device Driver. See also description of NtDeviceIoControlFile function.

FileHandle

HANDLE to File System Device Object opened as a file.

Event

Optional HANDLE to Event Object.

ApcRoutine

Optional pointer to user's APC Routine.

ApcContext

Parameter for ApcRoutine.

IoStatusBlock

IO result of call.

FsControlCode

Control Code typically defined as FSCTL_*.

InputBuffer

User's allocated buffer contains input data.

InputBufferLength

Length of InputBuffer, in bytes.

OutputBuffer

User's allocated buffer for results of call.

OutputBufferLength

Length of OutputBuffer, in bytes.

Documented by

Tomasz Nowak
ReactOS