ACC: Dos funciones para calcular la antigüedad en meses y años

   '==========================================================
   ' General Declaration
   '==========================================================

    Option Explicit

   '*************************************************************
   ' FUNCTION NAME: Age()
   '
   ' PURPOSE:
   '    Calculates age in years from a given date to today's date.
   '
   ' INPUT PARAMETERS:
   '    StartDate: The beginning date (for example, a birth date).
   '
   ' RETURN
   '    Age in years.
   '*************************************************************

    Function Age (varBirthDate As Variant) As Integer
       Dim varAge As Variant

      If IsNull(varBirthdate) then Age = 0: Exit Function

      varAge = DateDiff("yyyy", varBirthDate, Now)
      If Date < DateSerial(Year(Now), Month(varBirthDate), _
                           Day(varBirthDate)) Then
         varAge = varAge - 1
      End If
      Age = CInt(varAge)
    End Function

    '*************************************************************
    ' FUNCTION NAME: AgeMonths()
    '
    ' PURPOSE:
    '  Compliments the Age() function by calculating the number of months
    '  that have expired since the last month supplied by the given date.
    '  If the given date is a birthday, the function returns the number of
    '    months since the last birthday.
    '
    ' INPUT PARAMETERS:
    '    StartDate: The beginning date (for example, a birthday).
    '
    ' RETURN
    '    Months since the last birthday.
    '*************************************************************
    Function AgeMonths(ByVal StartDate As String) As Integer
      Dim tAge As Double
      tAge = (DateDiff("m", StartDate, Now))
      If (DatePart("d", StartDate) > DatePart("d", Now)) Then
          tAge = tAge - 1
      End If

      If tAge < 0 Then
         tAge = tAge + 1
      End If

      AgeMonths = CInt(tAge Mod 12)

    End Function