5.1. Memory model basics

There are two aspects to the memory model: the basic structural aspects, which relate to how things are laid out in memory, and then the concurrency aspects. The structural aspects are important for concurrency, especially when you’re looking at low-level atomic operations, so I’ll start with those. In C++, it’s all about objects and memory locations.

5.1.1. Objects and memory locations

All data in a C++ program is made up of objects. This is not to say that you can create a new class derived from int, or that the fundamental types have member functions, or any of the other consequences often implied when people say “everything is an object” when discussing a language like Smalltalk or Ruby. It’s just a statement about the building blocks of data in C++. The C++ Standard defines an object as “a region of storage,” although it goes on to assign properties to these objects, such as their type and lifetime.