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#### 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