<jargon> /hi:'zen-buhg/ (From Heisenberg's Uncertainty Principle in quantum physics) A bug that disappears or alters its behaviour 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 uninitialised memory, behaves quite differently.)
, nine out of ten heisenbugs result from uninitialised auto variables, fandango on core
phenomena (especially lossage related to corruption of the malloc arena
) or errors that smash the stack
Opposite: Bohr bug
See also mandelbug