The keyword arguments control which type of access cause a break:
Non- nil means break on reading a slot. The default is t .
Non- nil means break on writing a slot. The default is t .
t means break on all slots, otherwise this should be a list of symbols which are the slot-names on which to break. The default is t .
When non- nil , the debugger is entered. When nil , messages are printed to *trace-output* .
A common use of this function is to find where a slot is being changed in a complex program.
A useful debugging function which causes access to instance to invoke the trace facilities. Accesses include calls to slot-names and accessor function defined by the class of instance . Other instances of the same class are unaffected and your can remove the break by calling close:untrace-on-access . Breaks to the debugger when an instance of a class is accessed.
This function, when used with the break keyword, replaces the deprecated function break-on-access .