Re: assertions: does it matter that they are disabled in production?
peter koch larsen wrote:
On 9 Aug., 17:59, Walter Bright <wal...@digitalmars-nospamm.com>
wrote:
marlow.and...@googlemail.com wrote:
Does this mean C++ programmers don't like such a C-like mechanism? Or
they don't don't like the fact that the assertions are disabled in
production? Or is there some other reason?
I use them in the production release, and find them to be very effective
at finding bugs.
So perhaps you ship to early? ;-)
More like I've had the hubris that my code is perfect beaten out of me.
If I am to be more serious, something like "assert" can be quite
useful in production code. The problem is that assert in my opinion is
to coarse and perhaps to badly defined (I would not like a debugger to
be opened when the customer tries to run my code).
That doesn't happen on mine, it just prints a message indicating a
compiler bug and the user (hopefully) reports it to me with a
reproducible test case.
I started using asserts heavily back in the DOS days, where an errant
pointer could literally scramble your hard disk. This is absolutely
unacceptable behavior, so the asserts were effective in blunting that risk.
Some asserts are useful to leave in, but others are better left out. A
typical example is verification of code: assume you write a smart
o(log n) algorithm to replace your current o(n). In those cases, I
validate my new algorithm against the old one, but the result is that
your code gets slower, not faster. Using assert to validate this is
clearly a bad idea.
Sure, you have to use some judgment. I'm willing to put up with a 5%
slowdown for the extra checking, though. It has paid off handsomely for me.
Building a bit of redundancy into the data structures helps a great deal
in detecting corrupted data.
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