Allocators, introduced in Section 4.6, page 57, represent a special memory model and are an abstraction used to translate the need to use memory into a raw call for memory. This chapter describes allocators and corresponding low-level features to deal with memory. Details are provided in a supplementary section of the book, available at the book’s Web site: http://www.cppstdlib.com.
For the application programmer, using different allocators should be no problem. You simply have to pass the allocator as a template argument. For example, the following statements create different containers and strings, using the special allocator