Difference between revisions of "cpp/memory/scoped allocator adaptor"
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| − | The {{tt|std::scoped_allocator_adaptor}} class template is an allocator which can be used with multilevel containers (vector of sets | + | The {{tt|std::scoped_allocator_adaptor}} class template is an allocator which can be used with multilevel containers (vector of sets of lists of tuples of maps, etc). It is instantiated with one outer allocator type {{tt|OuterAlloc}} and zero or more inner allocator types {{tt|InnerAlloc...}}. A container constructed directly with a {{tt|scoped_allocator_adaptor}} uses {{tt|OuterAlloc}} to allocate its elements, but if an element is itself a container, it uses the first inner allocator. The elements of that container, if they are themselves containers, use the second inner allocator, etc. If there are more levels to the container than there are inner allocators, the last inner allocator is reused for all further nested containers. |
For the purpose of {{tt|scoped_allocator_adaptor}}, if the next inner allocator is {{tt|A}}, any class {{tt|T}} for which {{cpp|1=std::uses_allocator<T,A>::value == true}} participates in the recursion as if it was a container. Additionally, {{cpp|std::pair}} is treated as such a container by specific overloads of {{l2tt|cpp/memory/scoped_allocator_adaptor/construct}}. | For the purpose of {{tt|scoped_allocator_adaptor}}, if the next inner allocator is {{tt|A}}, any class {{tt|T}} for which {{cpp|1=std::uses_allocator<T,A>::value == true}} participates in the recursion as if it was a container. Additionally, {{cpp|std::pair}} is treated as such a container by specific overloads of {{l2tt|cpp/memory/scoped_allocator_adaptor/construct}}. | ||
Revision as of 00:47, 27 March 2012
Template:cpp/memory/scoped allocator adaptor/sidebar Template:ddcl list begin <tr class="t-dsc-header">
<td><scoped_allocator>
<td></td> <td></td> </tr> <tr class="t-dcl ">
<td >class scoped_allocator_adaptor : public OuterAlloc;
<td class="t-dcl-nopad"> </td> <td > (since C++11) </td> </tr> Template:ddcl list end
The std::scoped_allocator_adaptor class template is an allocator which can be used with multilevel containers (vector of sets of lists of tuples of maps, etc). It is instantiated with one outer allocator type OuterAlloc and zero or more inner allocator types InnerAlloc.... A container constructed directly with a scoped_allocator_adaptor uses OuterAlloc to allocate its elements, but if an element is itself a container, it uses the first inner allocator. The elements of that container, if they are themselves containers, use the second inner allocator, etc. If there are more levels to the container than there are inner allocators, the last inner allocator is reused for all further nested containers.
For the purpose of scoped_allocator_adaptor, if the next inner allocator is A, any class T for which Template:cpp participates in the recursion as if it was a container. Additionally, Template:cpp is treated as such a container by specific overloads of scoped_allocator_adaptor::construct.
Contents |
Member types
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Member functions
| creates a new scoped_allocator_adaptor instance (public member function) | |
| destructs a scoped_allocator_adaptor instance (public member function) | |
obtains an inner_allocator reference (public member function) | |
obtains an outer_allocator reference (public member function) | |
| allocates uninitialized storage using the outer allocator (public member function) | |
| allocates storage using the outer allocator (public member function) | |
| returns the largest allocation size supported by the outer allocator (public member function) | |
| constructs an object in allocated storage, passing the inner allocator to its constructor if appropriate (public member function) | |
| desrtucts an object in allocated storage (public member function) | |
| copies the state of scoped_allocator_adaptor and all its allocators (public member function) |
Non-member functions
| compares two scoped_allocator_adaptor instances (public member function) |
