Check maximum possible length

usually sizeof() should give you what you want. havent tested it, but sizeof() can be used for nearly all types to get its memory usage. example:

var
  s1: string[30];
  i1: byte;
begin
  i1:= sizeof(s1);  // should be 30
end;

How can I then do my routine?

 function PadRight(const S:String; C:Integer; Car:Char):string;
  begin
    Result:=S;
    if (Length(S)>C) then
      Result:=Copy(S, 1, C)
    else
    begin
      SetLength(Result, C);
      FillChar(Result[Length(S)+1], C, Car);
    end
  end;

procedure TForm1.Button1Click(Sender: TObject);
var
  a:string[10];
begin
  a:='some';
  a:=PadRight(a, SizeOf(a)-1, '0');
  ShowMessage(a)
end;

while length(s1)< sizeof(s1)- 1 do s1:= '0'+ s1;

hello  hulken, , I tried to make a procedure that would take any kind of shortString variable (like String[8] and String[21] and String[30] ) as a procedure parameter. . .  But I do not how to do that, and preserve the size charateristic of that declared variable? ?
So I did the following code, which will do what you want, without have the string variable as a parameter Type. . . I had to use pointers to do this in the  PadZero  procedure  below. . . .




procedure PadZero(pStr: PByte; NumChar, StrHigh: Byte);
var
pDes: PByte;
begin
// this does the Zero padding, but I used a PByte as the string type
if NumChar >= StrHigh then Exit;
pStr^ := StrHigh;
Inc(pStr);
pDes := pStr;
StrHigh := StrHigh-NumChar;
Inc(pDes, StrHigh);
MoveMemory(pDes, pStr, NumChar);
FillMemory(pStr, StrHigh, 48);
end;



procedure TForm1.ShortStr1Click(Sender: TObject);
var
Str16: String[16];
Str8: String[8];

begin
Str16 := 'Hello';
Str8 := 'Delphi?';

{I could NOT figure a way to pass a fixed string
 as a procedure parameter type and then get it's settings.
    So, you will need to use the PadZero procedure with the
    parmeters as a @ , Ord( ) and High( ) of that string}

PadZero(@Str16, Ord(Str16[0]), High(Str16));
ShowMessage(Str16);

PadZero(@Str8, Ord(Str8[0]), High(Str8));
ShowMessage(Str8);
end;


 = = = = = = = =  = = = = = = = = =
seems to work for me. . .
ask questions if you need more info