Consider the equation in the if statement:

var
  a, b : ansistring;
begin
  a := 'hello world..and a lot of other stuff to make this string long';
  b := a;
  if a=b then write ('idential');
end.

How is a=b evaluated? I hope/presume the text in the string is not taken into consideration at all, and that the system can immediately see that they are identical. Am I right?

Mark

No. How would the system know that? You can have two completely unrelated ansistrings with the same content (just do a readln() of two ansistrings and type in twice the same text), so a full string compare is necessary. It would be possible to make the comparison a two step process, in which we first check whether the ansistrings point to the same ansistring structure and only if that fails, start doing an actual string compare, but I doubt this will gain you much a most real world programs.

Jonas

Yes

Ok, I should check the source before replying :) Peter is right.

Jonas

Well...you answered your own question, Jonas, when you say "it would be possible"....

It would be possible to make the comparison a two step process, in which we first check whether the ansistrings point to the same ansistring structure and only if that fails, start doing an actual string compare,

MY question is...does FPC in fact do this?  In my example, a and b DO
point to the same ansistring structure, because b := a.

Peter Vremen has answered my question:

Yes.

And I am delighted with Peter's answer, but concerned that the two of you gave opposite answers.

Mark

To take away you concern, here is the source of the compare routine: Function fpc_AnsiStr_Compare(const S1,S2 : AnsiString): Longint;[Public,Alias : 'FPC_ANSISTR_COMPARE']; {$ifdef hascompilerproc} c
{

  Compares 2 AnsiStrings;
  The result is
   <0 if S1<S2
   0 if S1=S2

0 if S1>S2

}
Var
  MaxI,Temp : Longint;
begin
  if pointer(S1)=pointer(S2) then
   begin
     fpc_AnsiStr_Compare:=0;
     exit;
   end;
  Maxi:=Length(S1);
  temp:=Length(S2);
  If MaxI>Temp then
   MaxI:=Temp;
  Temp:=CompareByte(S1[1],S2[1],MaxI);
  if temp=0 then
   temp:=Length(S1)-Length(S2);
  fpc_AnsiStr_Compare:=Temp;
end;