Question

I’m working with Delphi 7 and Strings, and I came across this:

For a string of default length, that is, declared simply as string, max size is always 255. A ShortString is never allowed to grow to more than 255 characters.

Once I had to do something like this in my Delphi code (that was for a really big query):

var
  sMyStringOF256characters : String;
  ilength : Integer;
begin
  sMyStringOF256characters := 'ThisStringisofLength256,ThisStringisofLength256,.....'
  // length of sMyStringOF256characters is 256
end;

…I get this error:

[Error] u_home.pas(38): String literals may have at most 255 elements.

But when I try this:

var
  iCounter              : Integer;
  myExtremlyLongString  : String;
begin
  myExtremlyLongString := '';
  for iCounter := 0 to 2500 do
  begin
    myExtremlyLongString := myExtremlyLongString + IntToStr(iCounter);
  end;
  Label1.Caption := myExtremlyLongString;
  Label2.Caption := IntToStr(Length(myExtremlyLongString));
end; 

…the result is:

As you can see the length of myExtremlyLongString is 8894 characters. Why did Delphi not give any error saying the length is beyond 255 for myExtremlyLongString? I also used this but it doesn’t work:

SetLength(sMyStringOF256characters, 300);

Answer 1

why did not delphi give any error saying the length is beyond 255 for
myExtremlyLongString?

You have your answer a bit down in the text in section Long String (AnsiString).

In current versions of Delphi, the string type is simply an alias for
AnsiString,

So string is not limited to 255 characters but a string literal is. That means that you can build a string that is longer than 255 characters but you can not have a string value in code that is longer than 255 characters. You need to split them if you want that.

sMyString:='ThisStringisofLength255'+'ThisStringisofLength255';