.hst file format

Hi,

I'm trying my hand at .hst files but without any success so far. After a few searches I came across this post https://forum.mql4.com/60455 where I got the file format from.

If I run the below lines the values are zero. Maybe the format has changed (I have build 765) or my code is wrong or both. I can't figure it out.
I'm am trying to get to the end of the file, step back 60 bytes and read the bar info of the last available bar in the file. Any help would be welcome.

When I get this part right, I would like to change the bar info in the hst file. Does mql4 let you do that anyway without making it an off-line chart?

string hst_filename ="AUDCAD60.hst";

int hst_file = FileOpen(hst_filename, FILE_BIN|FILE_WRITE|FILE_READ);
 
if(hst_file<1)Print(GetLastError());
 
Print(FileSeek(hst_file,60,SEEK_END));
 
datetime ctm      = FileReadDatetime(hst_file);
double   open     = FileReadDouble(hst_file);
double   high     = FileReadDouble(hst_file);
double   low      = FileReadDouble(hst_file);
double   close    = FileReadDouble(hst_file);
long     volume   = FileReadInteger(hst_file);
int      spread   = FileReadLong(hst_file);
long real_volume  = FileReadLong(hst_file);
 
 Print(ctm);
 Print(open);
 Print(high);
 Print(low);
 Print(close);
 Print(volume);
 Print(spread);
       
 Print( FileTell(hst_file),"tell");
  

FileClose(hst_file);