Length
From the Scripting Manual
function Length(Text: string): integer; Parameter Info: Text (String): String to checks the length of. Description: This function will return the length of a string.
Examples
var
MyString: string;
begin
MyString := 'Hello World!';
WriteLn('"'+MyString+'" is '+inttostr(length(MyString))+' characters');
end;
Output: "Hello World" is 12 characters