Декларируем:
Public Const LOCALE_STHOUSAND = &HF
Public Const LOCALE_SDECIMAL = &HE
Public Const LOCALE_SMONDECIMALSEP = &H16
Public Const LOCALE_SMONTHOUSANDSEP = &H17
Declare Function GetSystemDefaultLCID Lib "Kernel32" () As Long
Declare Function GetUserDefaultLCID Lib "Kernel32" () As Long
Declare Function GetLocaleInfo Lib "Kernel32" Alias "GetLocaleInfoA" _
(ByVal Locale As Long, _
ByVal LCType As Long, _
ByVal lpLCData As String, _
ByVal cchData As Long) As Long
Обращение к функции:
Public Function GetDecimalSep() As String
Dim strVal As String
strVal = String(16, Chr(0))
GetLocaleInfo GetUserDefaultLCID(), LOCALE_SDECIMAL, strVal, 16
GetDecimalSep = Left(strVal, InStr(1, strVal, Chr(0)) - 1)
End Function