Re: exception handling anti-patterns in documentation

From: Robert Ramey (ramey_at_[hidden])
Date: 2022-05-30 01:50:09

On 5/28/22 3:39 PM, Andrzej Krzemienski via Boost wrote:
> try {
>>    lib::function();
>> }
>> catch(lib::exception const&) {
>>    // handle failure
>> }
>>

Pretty good and reasonable answers.  These seem to boil down to, any 
kind of failure in lib::function (or below) we would handle at the point 
of failure hence if we need to throw an exception we've skipped over a 
failure case.  (paraphrasing - still not sure I get it).

I'm envisioning some that I think happens to me on a regular base. 
Inside of lib::function (or lower) I request a large memory allocation 
which I expect to almost never fail.  I can trap this failure.  If I 
return failure at each call up the chain, I end up doing a lot of "if" 
at each level making the code slower and messier.  And this slowness 
messiness happens even on cases where there is no failure.  I don't have 
exceptions in this scenario.

What I actually do in this case is throw a custom exception at the point 
of failure which gives me information of where I was and what I was 
doing when I requested this "too large" memory allocation.  This seems 
to be a very reasonable scenario to me.

Robert Ramey