Re: setter for deleter in boost::shared_ptr (and alike)
Abhishek Padmanabh ha scritto:
On 27 Sep, 04:37, Alberto Ganesh Barbati <AlbertoBarb...@libero.it>
wrote:
2) the type of the deleter must be Assignable, but it's only required to
be CopyConstructible. Just provide the deleter a private (deleted?)
assignment operator and you would need to rely onto explicit destruction
and placement new... not the code one can write by mistake and expect it
to work properly.
D (deleter) shall be CopyConstructible (ref: 20.6.6.2.1/9). So, should
one conclude that it must not be Assignable? Should this not be
explicitly mentioned or non-doable from the interface? Or do I have an
older copy of the draft?
Nono. You are just reading my statement in the wrong context.
CopyConstructible and Assignable are orthogonal concepts: neither one
implies the other. shared_ptr requires D only to be CopyConstructible,
so it may or may not also be Assignable. The point in my previous post
was that if D is CopyConstructible but not Assignable (for example
because its assignment operator is made private), then you couldn't
modify a deleter in the way proposed by Mr. Steinback.
Ganesh
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