free

Arguments: address

Gives the object allocated by malloc back to the system. free should not be called with an address which was not directly generated by excl:malloc or else generated from translating an address generated by the C malloc() function, and it should not be called with an address which represents an already-freed object.

Note on backward compatibility

In releases prior to 7.0, the symbols excl::malloc and excl::free named functions that were different from the functions named by the now exported symbols excl:malloc and excl:free. The old versions of excl::malloc and excl::free are equivalent to aclmalloc and aclfree. If any code from Allegro CL 6.2 calls excl::malloc or excl::free, those calls should be changed to calls to aclmalloc and aclfree.

Note on various Allegro CL malloc and free functions

The space allocated by excl:malloc and its C counterpart malloc() (described here collectively as "malloc") is different than the space allocated by excl:aclmalloc and the C aclmalloc() (described collectively as "aclmalloc"). Malloc allocates in space defined and maintained by the system, in whatever manner the system defines. Some operating systems allow the linking in of alternate versions of malloc() and its cohorts (usually including free(), calloc(), realloc(), and others), giving some flexibility in debugging malloc bugs (but of course this need arises much less often in Lisp programming). The aclmalloc functionalities are part of the Allegro CL library and allocate from space usually known as Aclmalloc heap space. aclmalloc is useful for allocating objects which should survive the rebirth of a dumped lisp.

The free and aclfree functionalities must always match objects to free with the mallocs of the same kind; i.e. one should never free an aclmalloc'd object, nor should one call an aclfree function on an object created with malloc. Note that one can mix aclmalloc/aclfree with aclmalloc-aligned/aclfree-aligned, but only after proper conversions are done; see ff:address-to-aligned and ff:aligned-to-address.

Copyright (c) 1998-2022, Franz Inc. Lafayette, CA., USA. All rights reserved.
This page was not revised from the 10.0 page.
Created 2019.8.20.