Re: Why no front-and-pop?

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 4 Aug 2009 21:50:05 -0400
Message-ID:
<#0xvW8WFKHA.2376@TK2MSFTNGP03.phx.gbl>
Tim Roberts wrote:

In the list-like STL classes (list, stack, deque, queue), it has
always seemed odd to me that popping the top element requires two
operations (x.front() and x.pop()). For many algorithms, it seems
much more natural to combine those two. Can anyone explain why STL
does not include "get_front_and_pop_it" primitives?


http://www.gotw.ca/gotw/008.htm

With combined front_and_pop, if the element's copy constructor may throw
then you may end up with the situation where the element was removed
from the container, but then never reached the caller. This violates the
strong exception safety guarantee (either the operations succeeds, or
exception is thrown and the object's state doesn't change).
--
With best wishes,
    Igor Tandetnik

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