9.2.22 invoke-debugger [Function]

invoke-debugger condition ⇒ #<NoValue>

Arguments and Values::

condition—a condition object.

Description::

invoke-debugger attempts to enter the debugger with condition.

If *debugger-hook* is not nil, it should be a function (or the name of a function) to be called prior to entry to the standard debugger. The function is called with *debugger-hook* bound to nil, and the function must accept two arguments: the condition and the value of *debugger-hook* prior to binding it to nil. If the function returns normally, the standard debugger is entered.

The standard debugger never directly returns. Return can occur only by a non-local transfer of control, such as the use of a restart function.

Examples::

 (ignore-errors ;Normally, this would suppress debugger entry
   (handler-bind ((error #'invoke-debugger)) ;But this forces debugger entry
     (error "Foo.")))
Debug: Foo.
To continue, type :CONTINUE followed by an option number:
 1: Return to Lisp Toplevel.
Debug>

Side Effects::

*debugger-hook* is bound to nil, program execution is discontinued, and the debugger is entered.

Affected By::

*debug-io* and *debugger-hook*.

See Also::

error , break