[FSAOskar]

Just set up a timer which increases a variable every second/minute.

Like:

Код:

new pOnlineTime[MAX_PLAYERS];

SetTimerEx("OnlineTime",  1000, 1, "i", playerid);

foward OnlineTime(playerid)
public OnlineTime(playerid)
{
      pOnlineTime[playerid]++;
      return 1;
}

You can do the same with minutes of course which is probably better.
Then calculate the hours from the minutes/seconds.