Allocator (C++)

Allocator (C++)

In C++, an allocator is a class template that defines memory model to be used by some parts of the Standard Template Library (STL). It encapsulates the details related to the allocation and deallocation of dynamic memory and provides an abstraction of memory allocation and deallocation strategy.

Overview

The allocator class template is a general interface for C++ memory allocation. It is a part of the C++ Standard Library and is defined in the <memory> header file. The default allocator for the STL is std::allocator, which uses operator new to allocate memory and operator delete to deallocate memory.

Usage

Allocators are used in the STL to control the memory of container classes like vector, list, and map. When a container needs to allocate memory, it uses its associated allocator. The allocator is specified as a template parameter when declaring the container.

Custom Allocators

In some cases, the default std::allocator may not be suitable for specific needs. For example, if you want to allocate memory from a shared memory segment, or if you want to use a garbage collector. In such cases, you can create a custom allocator by defining a class that meets the allocator requirements of the C++ Standard Library.

See Also

• Memory Management (C++)
• Standard Template Library
• malloc
• free

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