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This is an older version of Boost and was released in 2021. The current version is 1.91.0.
The type of polymorphic allocator used by the library.
Defined in header <boost/json/memory_resource.hpp>
template< class T> class polymorphic_allocator
This type alias is set depending on how the library is configured:
If the macro BOOST_JSON_STANDALONE
is not defined, this type will be an alias template for boost::container::pmr::polymorphic_allocator. Compiling a program
using the library will require Boost, and a compiler conforming to C++11
or later.
If the macro BOOST_JSON_STANDALONE
is defined, this type will be an alias template for std::pmr::polymorphic_allocator. Compiling a program
using the library will require only a compiler conforming to C++17 or later.
https://en.cppreference.com/w/cpp/memory/polymorphic_allocator
Convenience header <boost/json.hpp>