From the NannyMUD documentation

LAST CHANGE

2001-09-29

FUNCTION

NAME
        block_add_exp_hook - 


AVAILABILITY
        This function can be located in any object.
	The calls are generated from /obj/player.

DESCRIPTION
	When a player is about to earn XP (added XP > 0) this function is 
        called. If it return 1, the player will not earn any XP.

	ARGUMENTS

	block_add_exp_hook(
	  ({ the new amount of XP, 
	     the old amount of XP,
	     the added amount of XP,
             the object adding the XP
	  }),
	  the player
	)



SEE ALSO
        value_add_exp_hook in hooks/value_add_exp_hook