LispWorks User Guide and Reference Manual > 32 The HCL Package

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allocation-in-gen-num

Macro
Summary

Allocates objects from a specified generation within the scope of evaluating a number of forms in 32-bit LispWorks.

Package

hcl

Signature

allocation-in-gen-num gen-num &body body => result

Arguments

gen-num

An integer, which if out of range for a valid generation number is rounded either to the youngest or oldest generation.

If gen-num is negative, the specified generation is: the highest generation number + 1 - gen-num , so that an argument of -1 specifies the highest generation number.

body

The forms to be evaluated while the allocation generation has been temporarily set to gen-num .

Values

result

The result of evaluating body.

Description

Allocates objects from a specified generation during the extent of the evaluation of the body forms.

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.

Note: this macro is implemented only in 32-bit LispWorks. In 64-bit implementations, use apply-with-allocation-in-gen-num or the :allocation argument to make-array instead.

Examples
(allocation-in-gen-num
     1
   (setq tab (make-hash-table :size 1200
                              :test 'eq)
         arr (make-array 20)))
See also

apply-with-allocation-in-gen-num
make-array
set-default-generation
get-default-generation
*symbol-alloc-gen-num*


LispWorks User Guide and Reference Manual - 22 Dec 2009

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