Allocates objects from a specified generation within the scope of evaluating a number of forms.
An integer, which if out of range for a valid generation number is rounded either to the youngest or oldest generation.
is negative, the specified generation is: the highest generation number + 1 -
, so that an argument of -1 specifies the highest generation number.
The forms to be evaluated while the allocation generation has been temporarily set to
The result of evaluating body.
Allocates objects from a specified generation during the extent of the evaluation of the body forms.
(setq tab (make-hash-table :size 1200
arr (make-array 20)))
Normally objects are allocated from the first (youngest) generation, which assumes that they are short-lived. The storage allocator and garbage collector perform better if allocation of large numbers of non-ephemeral objects is done explicitly into a generation other than the youngest.
LispWorks Reference Manual - 6 Apr 2005