Attribute VB_Name = "LoggedInUserName"
Option Explicit

Private Declare Function apiGetUserName Lib "advapi32.dll" Alias _
    "GetUserNameA" (ByVal lpBuffer As String, nSize As Long) As Long

Function GetLoggedInUserName() As String
    Dim MaxBufferLength As Long
    MaxBufferLength = 255

    Dim UserNameBuffer As String
    UserNameBuffer = String$(MaxBufferLength - 1, 0)

    Dim APIResult As Long
    APIResult = apiGetUserName(UserNameBuffer, MaxBufferLength)

    If (APIResult > 0) Then
        GetLoggedInUserName = Left$(UserNameBuffer, MaxBufferLength - 1)
    Else
        GetLoggedInUserName = vbNullString
    End If
End Function

Public Sub UnitTest_LoggedInUserName()
    Debug.Print GetLoggedInUserName()
End Sub