NTFileSize

Option Explicit

Private Type LARGE_INTEGER
    low As Long
    high As Long
End Type
  
Private Type FILE_STANDARD_INFORMATION
    allocSize As LARGE_INTEGER
    EndOfFile As LARGE_INTEGER
    numberofLinks As Long
    deletePending As Boolean 'should this be 2 bytes or 1, unused bigger is safer
    directory As Boolean
End Type

'https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/ntifs/nf-ntifs-ntqueryinformationfile
'https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/ns-wdm-_io_status_block

Private Declare Function ZwQueryInformationFile Lib "ntdll" ( _
        ByVal handle As Long, _
        ByVal pioStatus As Long, _
        ByVal pFileInfoStruct As Long, _
        ByVal length As Long, _
        ByVal InfoClass As Long _
) As Long

Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" ( _
    ByVal lpFileName As String, _
    ByVal dwDesiredAccess As Long, _
    ByVal dwShareMode As Long, _
    ByVal lpSecurityAttributes As Long, _
    ByVal dwCreationDisposition As Long, _
    ByVal dwFlagsAndAttributes As Long, _
    ByVal hTemplateFile As Long _
) As Long

Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

Function h(x As Long) As String
    h = Right("00000000" & Hex(x), 8)
End Function

Function NTFileSize(pth As String) As String

    Dim hFile As Long, ret As Long, ioStatus As Currency '8 bytes
    Dim stdInfo As FILE_STANDARD_INFORMATION
    Const StdInfoClass = 5
    Const FILE_SHARE_READ = &H1, OPEN_EXISTING = &H3, GENERIC_READ = &H80000000

    hFile = CreateFile(pth, GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0)
     
    If hFile < 1 Then
        Debug.Print "Failed to open handle to: " & pth
        Exit Function
    End If
    
    ret = ZwQueryInformationFile(hFile, VarPtr(ioStatus), VarPtr(stdInfo), LenB(stdInfo), StdInfoClass)
    CloseHandle hFile

    If ret = 0 Then
        NTFileSize = h(stdInfo.EndOfFile.high) & "`" & h(stdInfo.EndOfFile.low)
    Else
        Debug.Print "ZwQueryInformationFile Failed ret = " & ret
    End If
    
End Function

Private Sub Form_Load()
    On Error Resume Next
    Dim pth As String, f As Long
    pth = App.Path & "\test.txt"
    Debug.Print "Target: " & pth
    Kill pth
    f = FreeFile
    Open pth For Binary As f
    Put f, , "test"
    Close f
    Debug.Print NTFileSize(pth)
    Kill pth
End Sub