First page Back Continue Last page Overview Graphics
Quietly observing
Useful for Heisenbugs: From the Jargon file:
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. (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.
Notes:
Often bugs don't easily roll over and die in the presence of a debugger - sometimes they are more sneaky.