hab (HAB) - input
ulCodepage (ULONG) - input
If a non-existent code page is specified for ulCodepage, the code page specified by the queue associated with the calling thread is used.
ulCountry (ULONG) - input
pszStart (PSZ) - input
pszCurrentChar (PSZ) - input
pszPrevChar (PSZ) - returns
The previous character, or the first character if pszCurrentChar is the first character of pszStart.