Re: Assertion vs Exception Handling

From:

"Daniel T." <daniel_t@earthlink.net>

Newsgroups:

comp.lang.c++

Date:

Mon, 15 Mar 2010 10:54:51 -0400

Message-ID:

<daniel_t-32E7DF.10545115032010@70-3-168-216.pools.spcsdns.net>

Ian Collins <ian-news@hotmail.com> wrote:

On 03/15/10 03:03 PM, Daniel T. wrote:

I define [an error] as something the program cannot recover from.
When the design says, "If the user does X, then the program must to
Y," I don't call it an error when the user does X. If the design
requires that condition A must pertain at point B, and condition A
does not pertain at point B; I call *that* an error.

Exceptions are for exceptional circumstances. If something that
shouldn't fail fails, that's and exceptional circumstance. That's why
I mentioned file opening failing, if the file should be there, throw
if it isn't. If it's expected to sometimes not be there, deal with it
on the spot.

The above is essentially what I have been saying all along. How are our
positions different again?

If something is guaranteed not to happen, assert if it does!

I would add that you only should use the assert macro if you know for a
fact that every program that might ever use the function in question
will find aborting without cleanup an acceptable alternative.