procedure txtlog(str: string);
const
sLogPath = 'C:\mylog.txt';
var
logfile : TextFile;
begin
if not FileExists(sLogPath) then
begin
AssignFile(logfile, sLogPath);
ReWrite(logfile);
CloseFile(logfile);
end;
AssignFile(logfile, sLogPath);
Append(logfile);
Writeln(logfile, FormatDateTime('yyyy/mm/dd HH:nn:ss',now)+': '+str);
Flush(logfile);
CloseFile(logfile);
end;