Do you want to stay ahead of the curve and start to use polymorphic allocators in your projects? Are you undeterred even by the cost of virtual calls? If so, it's time to talk about the nuances with a lifetime and why you can't just replace containers with analogs from the 'pmr' namespace.

How frivolous use of polymorphic allocators can imbitter your life

by Grigory Semenchev

From the article:

The developers' prayers have been answered! Starting with C++17, you can use polymorphic allocators. Their idea is a little different from what we need. What is important is that they allow you to specify a buffer from which the allocator will take memory. Such a buffer is called a resource, and it must be inherited from std::memory_resource. It's also important that C++17 introduced several standard resources. Let's examine std::unsynchronized_pool_resource as an example. I should admit that all options mentioned in this article mostly apply to all standard library resources.