#HEISENBERG PRINCIPLE VS SCHRODINGER CAT SOFTWARE#
#HEISENBERG PRINCIPLE VS SCHRODINGER CAT CODE#

Heisenbugs can be viewed as instances of the observer effect in information technology. This is particularly true when the behavior involves interaction with an entity not under the control of a debugger, such as when debugging network packet processing between two machines and only one is under debugger control. Time-sensitive bugs, such as race conditions, may not occur when the program is slowed down by single-stepping source lines in the debugger. Executing a program under control of a debugger can change the execution timing of the program as compared to normal execution. Time can also be a factor in heisenbugs, particularly with multi-threaded applications.

#HEISENBERG PRINCIPLE VS SCHRODINGER CAT CODE#

Debuggers also commonly allow the use of breakpoints or provide other user interfaces that cause additional source code (such as property accessors) to be executed stealthily, which can, in turn, change the state of the program. Other common causes of heisenbugs are using the value of a non-initialized variable (which may change its address or initial value during debugging), or following an invalid pointer (which may point to a different place when debugging). Similarly, heisenbugs may be caused by side-effects in test expressions used in runtime assertions in languages such as C and C++, where the test expression is not evaluated when assertions are turned off in production code using the NDEBUG macro. This may affect, for instance, the result of floating-point comparisons, since the value in memory may have smaller range and accuracy than the value in the register.

While debugging, values that an optimized program would normally keep in registers are often pushed to main memory.

One common example of a heisenbug is a bug that appears when the program is compiled with an optimizing compiler, but not when the same program is compiled without optimization (as is often done for the purpose of examining it with a debugger).

Heisenbugs occur because common attempts to debug a program, such as inserting output statements or running it with a debugger, usually have the side-effect of altering the behavior of the program in subtle ways, such as changing the memory addresses of variables and the timing of its execution.

#HEISENBERG PRINCIPLE VS SCHRODINGER CAT SOFTWARE#

Similar terms, such as bohrbug, mandelbug, hindenbug, and schrödinbug (see the section on related terms) have been occasionally proposed for other kinds of unusual software bugs, sometimes in jest. In electronics, the traditional term is probe effect, where attaching a test probe to a device changes its behavior. The term is a pun on the name of Werner Heisenberg, the physicist who first asserted the observer effect of quantum mechanics, which states that the act of observing a system inevitably alters its state. In computer programming jargon, a heisenbug is a software bug that seems to disappear or alter its behavior when one attempts to study it.

Heisenberg principle vs schrodinger cat