Condition Types

ANSI Common Lisp

9 Conditions

9.1 Condition System Concepts

9.1.1 Condition Types

The next figure lists the standardized condition types. Additional condition types can be defined by using define-condition.

Standardized Condition Types
arithmetic-error	floating-point-overflow	simple-type-error
cell-error	floating-point-underflow	simple-warning
condition	package-error	storage-condition
control-error	parse-error	stream-error
division-by-zero	print-not-readable	style-warning
end-of-file	program-error	type-error
error	reader-error	unbound-slot
file-error	serious-condition	unbound-variable
floating-point-inexact	simple-condition	undefined-function
floating-point-invalid-operation	simple-error	warning

All condition types are subtypes of type condition. That is,

 (typep c 'condition)  true

if and only if c is a condition.

Implementations must define all specified subtype relationships. Except where noted, all subtype relationships indicated in this document are not mutually exclusive. A condition inherits the structure of its supertypes.

The metaclass of the class condition is not specified. Names of condition types may be used to specify supertype relationships in define-condition, but the consequences are not specified if an attempt is made to use a condition type as a superclass in a defclass form.

The next figure shows operators that define condition types and creating conditions.

Operators that define and create conditions.
define-condition	make-condition

The next figure shows operators that read the value of condition slots.

Operators that read condition slots.
arithmetic-error-operands	simple-condition-format-arguments
arithmetic-error-operation	simple-condition-format-control
cell-error-name	stream-error-stream
file-error-pathname	type-error-datum
package-error-package	type-error-expected-type
print-not-readable-object	unbound-slot-instance

9.1.1.1 Serious Conditions