Heisenbug /hi:'zen-buhg/ N.
[from Heisenberg's
Uncertainty Principle In Quantum Physics] A Bug That Disappears Or
Alters Its Behavior When One Attempts To Probe Or Isolate It.
[from Heisenberg's
Uncertainty Principle in quantum physics] A bug that disappears or
alters its behavior when one attempts to probe or isolate it.
(This usage is not even particularly fanciful; the use of a
debugger sometimes alters a program's operating environment
significantly enough that buggy code, such as that which relies on
the values of uninitialized memory, behaves quite differently.)
Antonym of Bohr bug; see also mandelbug,
schroedinbug. In C, nine out of ten heisenbugs result from
uninitialized auto variables, fandango on core phenomena
(esp. lossage related to corruption of the malloc arena) or
errors that smash the stack.
aliasing bug: n. A class of subtle programming errors that can
arise in code that does dynamic allocation, esp. via
`malloc(3)' or equivalent. If several pointers address
(`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}....
aliasing bug n.
A class of subtle programming errors that
can arise in code that does dynamic allocation, esp. via
malloc(3) or equivalent. If several pointers address
(`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....
fandango on core n.
[Unix/C hackers, from the Iberian
dance] In C a wild pointer that runs out of bounds, causing a
core dump, or corrupts the malloc(3) arena in such
a way as to cause mysterious failures later on, is sometimes said
to have `done a fandango on core'....
