function GetAbsPath(CurPath:Widestring;DirPath:Widestring):Widestring;
var Buffer:array[0..MAX_PATH - 1] of WideChar;
    cBuf:Cardinal;
begin
  cBuf:=sizeof(Buffer);
  InternetCombineUrlW(PWideChar(CurPath),PWideChar(DirPath),
    Buffer,cBuf,ICU_BROWSER_MODE);
  Result:=StrPasW(Buffer);
end;这里的 buffer 长度只有 259 , 如果长度超过这个数字就会出错。PWideChar 的最大长度是多少?