TSysCharSet = set of AnsiChar;
typedef System::Set<char,0,255> TSysCharSet;
TSysCharSet is a set of characters.
TSysCharSet is a set containing ANSI characters. TSysCharSet is useful when passing a set of characters to various functions that require them. TSysCharSet is primarily used in the CharInSet routine, which detects whether a given character is contained within the set.
Note: You cannot use TSysCharSet to group Unicode characters. This means that TSysCharSet cannot be used to check whether an Unicode character is a part of TSysCharSet.