[squid-dev] [PATCH] Non-zeroing mempools

[Alex Rousskov]

On 08/23/2015 04:22 PM, Kinkie wrote:
>> Omitting emplace and implementing the others as protected for
>> completeness' sake.

>     Why protected?
> 
>     * Making default constructor protected is the same as keeping it public
>     because the class is abstract (nobody can create a StoreMeta object).
> 
>     * If you want to prohibit copying, use "= delete" for copy constructor
>     and assignment operator. Given the class use of raw pointers, deleting
>     sounds like a good idea, but I did not study this class usage in detail.
>     In general, prohibiting dangerous operations is better than allowing
>     them so if "= delete" works well, we should use it.


> With private (on clang)

The default constructor should be _public_. Sorry if my explanation why
protected is essentially the same as public (in this context) made you
think that I recommended to make the default constructor private.


> StoreMeta.cc:100:22: error: call to implicitly-deleted default
> constructor of 'StoreMetaMD5'
>         result = new StoreMetaMD5;
>                      ^
> ../src/StoreMetaMD5.h:16:22: note: default constructor of 'StoreMetaMD5'
> is implicitly deleted because base class 'StoreMeta' has an inaccessible
> default constructor
> class StoreMetaMD5 : public StoreMeta
>                      ^

That error matches my expectations: Kids cannot access private parent
members, including constructors.


Hope this clarifies,

Alex.