Help: Pointers Problems

[altf4]

Events:

Private Sub Command1_Click()
    'Text2.Text = FormatFilePath(Text1.Text)
    Text2.Text = FormatFilePath2(Text1.Text)
End Sub

Private Function OpenFilePath(ByVal sPath As String) As String

    'Variables:
    Dim hFile As Long
    
    'Method 1:
        Dim OFS As OFSTRUCT
        hFile = OpenFile(sPath, OFS, OF_READWRITE)
    
    'Method 2:
        'Dim lReturn As Long
        'Dim tObjAttr As OBJECT_ATTRIBUTES
        'Dim tUString As UNICODE_STRING
    
        'Initialize attributes:
        'tUString.Length = Len(sPath) * 2
        'tUString.Buffer = StrPtr(sPath)
        
        'tObjAttr.Length = Len(tObjAttr)
        'tObjAttr.ObjectName = VarPtr(tUString)
        'tObjAttr.Attributes = OBJ_CASE_INSENSITIVE Or OBJ_INHERIT
        
        'Open File:
        'lReturn = ZwOpenFile(hFile, FILE_ALL_ACCESS, 0, tIO, FILE_SHARE_READ Or FILE_SHARE_WRITE, FILE_NON_DIRECTORY_FILE)
        'lReturn = NtOpenFile(hFile, GENERIC_READ Or SYNCHRONIZE, tObjAttr, tIO, FILE_SHARE_READ, FILE_NON_DIRECTORY_FILE Or FILE_SYNCHRONOUS_IO_NONALERT)
            'MsgBox GetSysMsg(lReturn0)

    'Return Value:
    OpenFilePath = hFile

End Function


Public Function FormatFilePath2(ByVal sPath As String) As String

    Dim tIO As IO_STATUS_BLOCK
    Dim tFileName As FILE_NAME_INFORMATION
    
    Dim hFile As Long
    Dim lReturn As Long
    
    '-----------
    
    'Open File:
    hFile = OpenFilePath(sPath)
        MsgBox "hFile  = " & hFile
        
    'Set buffer & size:
    tFileName.FileName.Length = Len(sPath) * 2
    tFileName.FileName.Buffer = StrPtr(sPath)
    Call RtlInitUnicodeString(tFileName.FileName, StrPtr(sPath))
    
        MsgBox "Unicode Buff = " & tFileName.FileName.Buffer
        MsgBox "Unicode Length = " & tFileName.FileName.Length
        MsgBox "Unicode MaxLength = " & tFileName.FileName.MaximumLength
    
    'Store structure size:
    Dim lSize As Long
    lSize = Len(tFileName)
        MsgBox "lSize = " & lSize
    
    'Set pointer:
    Dim ptr As Long
    ptr = VarPtr(tFileName)
        MsgBox "Pointer = " & ptr
        MsgBox "Pointer Size = " & Len(ptr)
    
    'Fill data structure:
    lReturn = NtQueryInformationFile(hFile, tIO, ptr, lSize, FileNameInformation)
        MsgBox GetSysMsg(lReturn)
    
    'Move pointer to variable:
    Dim tFNI As FNI
    
        'Init Unicode string maybe? (Still does not work)
        tFNI.FileName.Length = Len(sPath) * 2
        tFNI.FileName.Buffer = StrPtr(sPath)
        Call RtlInitUnicodeString(tFNI.FileName, StrPtr(sPath))
    
    'Call CopyMemory(tFNI, ByVal ptr, Len(ptr))
    'Call CopyMemory(ByVal VarPtr(tFNI), ByVal ptr, lSize)
    'Call CopyMemory(VarPtr(tFNI), ByVal ptr, Len(ptr))
    'Call CopyMemoryRead(ByVal VarPtr(tFNI), ByVal VarPtr(ptr), Len(ptr))
    
    Call CopyMemory(ByVal VarPtr(tFNI), ByVal ptr, LenB(tFNI))
    
    
        MsgBox "tFNI Size = " & Len(tFNI)
        
        MsgBox "Unicode Buff = " & tFNI.FileName.Buffer
        MsgBox "Unicode Length = " & tFNI.FileName.Length
        MsgBox "Unicode MaxLength = " & tFNI.FileName.MaximumLength
    
    Dim sValue As String
    sValue = Space(tFNI.FileName.Length \ 2)
        MsgBox "sValue Buff = " & sValue
    'Call CopyMemoryRead(sValue, ByVal tFNI.FileName.Buffer, (Len(tFNI.FileName.Buffer)))
    'Call CopyMemory(ByVal VarPtr(sValue), tFNI.FileName.Buffer, 4)
    Call CopyMemory(ByVal StrPtr(sValue), tFNI.FileName.Buffer, tFNI.FileName.Length)
        MsgBox "sValue = " & sValue

End Function

The problem is right here:

    'Move pointer to variable:
    Dim tFNI As FNI
    
        'Init Unicode string maybe? (Still does not work)
        tFNI.FileName.Length = Len(sPath) * 2
        tFNI.FileName.Buffer = StrPtr(sPath)
        Call RtlInitUnicodeString(tFNI.FileName, StrPtr(sPath))
    
    'Call CopyMemory(tFNI, ByVal ptr, Len(ptr))
    'Call CopyMemory(ByVal VarPtr(tFNI), ByVal ptr, lSize)
    'Call CopyMemory(VarPtr(tFNI), ByVal ptr, Len(ptr))
    'Call CopyMemoryRead(ByVal VarPtr(tFNI), ByVal VarPtr(ptr), Len(ptr))
    
    Call CopyMemory(ByVal VarPtr(tFNI), ByVal ptr, LenB(tFNI))

Notice how I tried the method you described in there.

See if you have any idea why it does this. To create it just add it to a form and put 1 command button and 2 textboxes on it.

Eneter a valid file path in textbox 1 and see what happens. It will go up to the point, the API will be successful, and then boom crashes.

Please Help.


OR

Here I uploaded my code, just add a text file called A.txt to C:\ and click the command button and watch it crash right after the Error_Success Return from the API:
http://www.mediafire.com/?7rzkn1ldywe

So please help if you can.