stale pointer bug

programming (Or "aliasing bug") A class of subtle

programming errors that can arise in code that does dynamicallocation, especially via malloc or equivalent.

If several pointers address (are "aliases for") a given hunk

of storage, it may happen that the storage is freed or

reallocated (and thus moved) through one alias and then

referenced through another, which may lead to subtle (and

possibly intermittent) lossage depending on the state and the

allocation history of the malloc arena. This bug can be

avoided by never creating aliases for allocated memory, or by

use of a higher-level language, such as Lisp, which

employs a garbage collector.

The term "aliasing bug" is nowadays associated with C

programming, it was already in use in a very similar sense in

the ALGOL 60 and Fortran communities in the 1960s.

See also smash the stack, fandango on core, memory leak,

memory smash, spam.

[Jargon File]

(1995-05-09)