TOPIC:

if SPD.Execute then [color=#4400ff]//don't ask why, but SPD is of TSaveFileDialog class[/color]
           begin
                [color=#ff0000]path:=Utf8ToSys(ExtractFilePath(SPD.FileName));
                nam:=UTF8ToSys(ExtractFileNameOnly(SPD.FileName));[/color] [color=#4400ff]//here I change IDE's utf8 into system cp, right? Right?[/color]
                s:=TMemoryStream.Create;
                s.Write(Length(icons.icons),sizeof(integer));
                i:=1; s.Write(i,sizeof(byte));
                for i:= 0 to length(icons.icons) - 1 do
                    begin
                         s.WriteAnsiString(icons.icons[i].name);
                         ForceDirectories(path+nam);
                           //now ^ THIS works fine with russian letters and I have my folder created :) 

                         icons.icons[i].graphic.SaveToFile(path+nam+PathDelim+'pix_'+inttostr(i)+'.png');
                           // ^ but this line produces exception! 
                           // My program can't create file "??????? ????". 
                           // Yep, instead this "?" there should be russian characters. 
                           // Oh, icons.icons[i].graphic is of TPortableNetworkGraphic 
                           // class...[/color]
                    end;
             s.SaveToFile(ChangeFileExt(spd.FileName,'.sat'));
             s.Free;
             exit;
        end;

function ChangeFileExt2(const aFileName, aExtension: string): string;
  var
    c1,c2:integer;
    ss1:string;
 begin
    result:='';
    ss1:='';
    if aFileName='' then exit;

    c1:=Length(aFileName);
    c2:=Length(aExtension);

    if c2<1 then
     begin
         result:=aFileName+'.'+aExtension;
     end else
     begin
         ss1:=LeftStr(aFileName,c1-c2-1);
         result:=ss1+'.'+aExtension;
     end;
 end;

RenameFileUTF8(tempname, utf8name) 

program testutf8;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes  ,
  { you can add units after this }
   SysUtils , FileUtil
  ;
var
  utf8name, tempansiname :string;
  testlist: TStringlist;
begin
   testlist := TStringList.create();
   testlist.Append('That is 0x03E2 = Ϣ');
   utf8name := 'ϢϢϢ.txt'  ;
   //testlist.SaveToFile(UTF8ToSys(utf8name)); // unable to create file ???.txt
   //testlist.SaveToFile(SysToUTF8(utf8name)); // creates wrong filename: ϢϢϢ.txt
   //testlist.SaveToFile(utf8name);            // creates wrong filename: ϢϢϢ.txt
   tempansiname := 'temp8899.tmp';
   testlist.SaveToFile(tempansiname);          // creates temp filename: temp8899.tmp
   RenameFileUTF8(tempansiname, utf8name);     // creates correct filename: ϢϢϢ.txt
end.