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From: Bonita Montero <Bonita.Montero@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: Top 10 most common hard skills listed on resumes...
Date: Tue, 27 Aug 2024 11:47:45 +0200
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Am 27.08.2024 um 11:32 schrieb David Brown:

> On 27/08/2024 10:36, Bonita Montero wrote:

>> C++ is efficient and abstract in one.

> Any simple one-line claim here is clearly going to be wrong.

90% of the C++-abstractions are zero-cost abstractons.

> C++ code can be efficient, or abstract, or both, or neither.

Of course it can. Imagine functional programming with a std::sort.
It's abstract since you won't have to deal with the details of the
sort and supply only a comparison function object, but it's still
optimally performant.

>> You have to accept exceptions with C++ since there are a lot of places
>> where C++ throws a bad_alloc or system_error.

> Incorrect.  Like most low-level or systems programmers using C++, I have 
> exceptions disabled and never use them.

You won't be able to change the runtime's behaviour with that. The
runtime trows bad_alloc or system_error everywhere and if you disable
exceptions the application simply terminates if this is thrown.

> Incorrect.

I just measured the tim of a ...

	virtual int fn( int, int )

.... which adds only two ints. The overhead is about one nanosecond
on my Zen4-CPU. And usually you do complex tasks inside the virtual
function so that the call itself doens't participate much in the
overall computation time.

> Virtual function overhead will sometimes be worth the cost, and in some 
> circumstances it can be less than more manual dispatch methods.  But it 
> is not cost-free, and the overhead can most certainly be relevant if it 
> is used inappropriately.

If the destination of the dispatch varies the overhead is nearly the
same as with static dispatch since most of the time takes the mispre-
dicted branch.