[Gammix]

1) Use arrays for storing object position. For example:

pawn Код:

enum objectsenum
{
    Float:ox,
    Float:oy,
    Float:oz
}
new Objects[MAX_OBJECTS][objectsenum];

MAX_OBJECTS can be your own value too.

Now when you create a object, just save the coords of position of object while creating. For example:

pawn Код:

CreateObject(model, X, Y, Z, rX, rY, r)
Objects[i][ox] = X, Objects[i][oy] = Y, Objects[i][oz] = Z;

You can also hook CeateObject.

Now onplayerupdate, i don't recommend onplayerupdate though.

pawn Код:

public OnPlayerUpdate(playerid)
{
    for(new i; i < MAX_OBJECTS; i++)
    {
        if(IsValidObject(i))
        {
            if(IsPlayerInRangeOfPoint(playerid, 5.0, Objects[i][ox], Objects[i][oy], Objects[i][oz]))
            {
                SendClientMessage(playerid, -1, "your msg");
            }
        }
    }
    return 1;
}