1 The CLOS Package

trace-on-access

Function

Summary

Invokes the trace facilities when an instance of a class is accessed.

Package

clos

Signature

trace-on-access instance &key read write slot-names break => t

Arguments

The keyword arguments control which type of access cause a break:

read: Non-nil means break on reading a slot. The default ist.
write: Non-nil means break on writing a slot. The default ist.
slot-names: 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 ist.
break: When non-nil, the debugger is entered. Whennil, 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.

Values

Returnst.

Description

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 callingclose: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 functionbreak-on-access.