Error compiling pike script

/srv/www/users/hugo/tmp/pike/a.pike:7	Error: Too few arguments to trace (got 0).
/srv/www/users/hugo/tmp/pike/a.pike:7	Error: Expected: int.
/srv/www/users/hugo/tmp/pike/a.pike:7	Error: Function type:
/srv/www/users/hugo/tmp/pike/a.pike:7	Error: Got     : function(int, void | string, void | int : int).