On Tue, Oct 18, 2011 at 12:21, Vicente J. Botet Escriba < vicente.botet@wanadoo.fr> wrote:
Le 18/10/11 17:07, Marshall Clow a écrit :
On Oct 18, 2011, at 6:42 AM, Dave Abrahams wrote:
on Mon Oct 17 2011, Marshall Clow<mclow.lists-AT-gmail.com> wrote:
[heading Exception Safety]
All of the variants of `all_of` and `all_of_equal` take their parameters by value or const reference, and do not depend upon any global state. Therefore, all the routines in this file provide the strong exception guarantee.
It may be true, but it's not an appropriate conclusion from the premises. std::copy also takes all its parameters by value.
Good point - how would you state it, then? "Only reads from the iterators" is the key point (unlike std::copy)
Maybe because these functions don't modify anything?
Vicente
I think the appropriate wording is "All variants of 'all_of' and 'all_of_equal' have no side effects, and therefore provide the strong exception guarantee." The first-order predicate logic equivalence "( for_all_x p(x) ) == not ( for_some_x not p( x ) )" is a very good reason for 'all_of' and 'all_of_equal' to return true when given the empty set as input. -- Casey Carter