Create folder in temp directory

Considered the following code:

Code:

---

Private Declare Function GetTempPath Lib "kernel32" Alias "GetTempPathA" _
                (ByVal nBufferLength As Long, _
                ByVal lpBuffer As String) As Long
Private Declare Function GetTempFileName Lib "kernel32" Alias "GetTempFileNameA" (ByVal lpszPath As String, ByVal lpPrefixString As String, ByVal wUnique As Long, ByVal lpTempFileName As String) As Long

Public Function GetTempDir() As String
    Dim sBuffer As String
    Dim lRetVal As Long

    sBuffer = String(255, vbNullChar)

    lRetVal = GetTempPath(Len(sBuffer), sBuffer)

    If lRetVal Then
        GetTempDir = Left$(sBuffer, lRetVal)
    End If
End Function

Private Sub Command1_Click()
Dim sBuffer As String
 sBuffer = String$(255, vbNullChar)
GetTempFileName GetTempDir(), "aaa", 0, sBuffer
MsgBox sBuffer

End Sub

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My question is:
1)Does the code above guarantee to generate a unique filename?
2)This code can only generate file with .tmp extension in user temp directory, how to create a folder with unique name?

Easiest would be to keep generating temp file names with the .tmp extension to a string, stripping the .tmp and adding whatever extension you like, then checking to see if the new filename exists. Lather, rinse, repeat until you find a unique one.

If the function fails, the return value is zero.

Do Until GetTempPath(Len(sBuffer), sBuffer)
Loop
'adjust sBuffer for Chr(0)
MkDir sBuffer