Delphi Pos always returning 0 - string

Question

I really don't know why Pos keep returning 0 instead of the char ";" position in string
I have to get a response of a php page which outputs a Content-Type: text/plain
So one example output is
2;fulano;fulano;0
3;ciclano;ciclano;0
4;beltrano;beltrano;0
5;foo;foo;0
8;jose;jose;0
9;maria;maria;0
and the code is
var
linha,uid,login,senha,email,tipo : WideString;
resposta : TStringList;
I : Integer;
begin
try
resposta := TStringList.Create;
resposta.Text := frmMain.IdHTTP1.Get(frmMain.cdsConfig.FieldByName('WebService').AsString+'listdest.php');
for I := 0 to resposta.Count-1 do
begin
linha := resposta.Strings[i];
if i = 0 then
Delete(linha,1,1); // the first line have one wierd $FEFF
if length(linha) > 5 then
begin
uid := Copy(linha,1,Pos(linha,';')-1);
Delete(linha,1,Pos(linha,';'));
login:=Copy(linha,1,Pos(linha,';')-1);
Delete(linha,1,Pos(linha,';'));
senha:=Copy(linha,1,Pos(linha,';')-1);
Delete(linha,1,Pos(linha,';'));
email:=Copy(linha,1,Pos(linha,';')-1);
Delete(linha,1,Pos(linha,';'));
tipo:=Copy(linha,1,Pos(linha,';')-1);
Delete(linha,1,Pos(linha,';'));
end;
end;
//dlgWait.Close;
except on E :Exception do
begin
MessageBox(Self.Handle,PWideChar(E.Message),'Erro',MB_OK+MB_ICONERROR+MB_APPLMODAL);
dlgWait.Close;
FreeAndNil(resposta);
end;
end;

Answer 1

Your call to Pos is backwards. The parameters are:
function Pos(const SubStr, Str: _ShortStr; Offset: Integer): Integer;
But your code assumes they are:
function Pos(const Str, SubStr: _ShortStr; Offset: Integer): Integer;
So actually what it's trying to do is look for the value of linha within ';', which of course unless linha = ';', it will return 0.
Another way to put it, as Rudy said, instead of looking for a needle in a haystack, your code is looking for a haystack in a needle.
Swap around the first and second parameters to these calls.
On a side note, just a tip for performance. Rather than calling Pos twice for each, keep a cached copy of the value...
P := Pos(';', linha);
uid := Copy(linha,1,P-1);
Delete(linha,1,P);