storage-condition,
serious-condition,
condition,
t
The type storage-condition consists of serious conditions that
relate to problems with memory management that are potentially due to
implementation-dependent limits rather than semantic errors
in conforming programs, and that typically warrant entry to the
debugger if not handled. Depending on the details of the implementation,
these might include such problems as
stack overflow,
memory region overflow,
and
storage exhausted.
While some Common Lisp operations might signal storage-condition
because they are defined to create objects,
it is unspecified whether operations that are not defined to create
objects create them anyway
and so might also signal storage-condition.
Likewise, the evaluator itself might create objects
and so might signal storage-condition.
(The natural assumption might be that such
object creation is naturally inefficient,
but even that is implementation-dependent.)
In general, the entire question of how storage allocation is done is
implementation-dependent,
and so any operation might signal storage-condition at any time.
Because such a condition is indicative of a limitation
of the implementation
or of the image
rather than an error in a program,
objects of type storage-condition are not of type error.