The only time usr is assigned for you is when a player (in Dream Seeker) executes a verb, clicks something with the mouse, or any other such action.
So if the player does something like click the mouse or run a verb, usr is set. When they view a stat panel, usr is set to them, since the stat panel they look at (set by client.statobj) doesn't have to be their own. When they log in, or log out on their own, usr is set. When they move of their own volition, usr is set.
So why isn't usr valid in movement procs like turf/Entered() or in mob/Logout()? The problem is that a player can be moved by other code in the game, not necessarily of their own free will, and they can be logged out automatically too. usr could well be null, or could be another player.
END EXCERPT
So in the case of Entered(), usr works if you move their via .north, .south, etc (arrow keys/numpad/arrows in DS). If the player is moved there by other methods, you will recieve runtime errors. And as most things in programming go, if it works 50% one way and 100% another, you use the method that works 100%.
According to the DM Reference:
The only time usr is assigned for you is when a player (in Dream Seeker) executes a verb, clicks something with the mouse, or any other such action.
So if the player does something like click the mouse or run a verb, usr is set. When they view a stat panel, usr is set to them, since the stat panel they look at (set by client.statobj) doesn't have to be their own. When they log in, or log out on their own, usr is set. When they move of their own volition, usr is set.
So why isn't usr valid in movement procs like turf/Entered() or in mob/Logout()? The problem is that a player can be moved by other code in the game, not necessarily of their own free will, and they can be logged out automatically too. usr could well be null, or could be another player.
END EXCERPT
So in the case of Entered(), usr works if you move their via .north, .south, etc (arrow keys/numpad/arrows in DS). If the player is moved there by other methods, you will recieve runtime errors. And as most things in programming go, if it works 50% one way and 100% another, you use the method that works 100%.