Error Processing

[JohnQ]

(The thread "Error Handling Idioms" prompted this post. I meant to post it
at the top level, but it got posted as a reply. So here it is again!)

An attempt at common defintions:

fault: the cause of error.
error: a detected fault.
error handling: planned processing (perhaps via formal mechanisms) that
occurs upon fault detection.
error correction: returning a program (or system) back to an error-free
state.
failure: deviation from specified behavior (such as that which occurs when
an fault is not detected or an error not corrected or aborting).
C++ exception mechanisms, function return codes: 2 ways to facilitate
transfer of control to error handling code.

Note that by the above definitions, it is not always obvious if failure has
occurred. Case A: If a stray electron caused a memory bit to toggle and
caused the program to restart but then behave from there on as expected, I'd
say that is not failure. Case B: OTOH, if the program continually restarts,
I'd call that a failure.

Case A

Fault: stray electron. Error: noted memory corruption. Handling: solves
problem. Failure: Yes. Recovery: Yes.

Case B

Fault: dunno. Error: noted memory corruption. Handling: does not solve
problem. Failure: Yes. Recovery: No.

There are more important things (such as understanding of failure modes) to
worry about than which mechanism one uses to transfer control to an error
handler, IMO. C++ exceptions don't help with detection or correction ('try'
is not detection and 'catch' is not correction), the most important parts.
Also, I think that maybe trying to talk about errors in general rather than
specific errors or categories of errors may be futile.

John