Rud Merriam | A Journey into Non-Virtual Polymorphism 2 Who Doesn’t Recognize This?? 1990 Borland Turbo C++Cppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 3 Background ● Experience – Medium.com (https://medium.com/@rudmerriam)Cppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 4 Polymorphism ● Greek: “many forms” (Obligatory statement) ● The use of a single variableCppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 5 Polymorphic Variables ● Base class pointer to derived class – Virtual functions are not bad! ● Standard Template Library

carePhoto by Tech Nick on unsplashSimple benchmark class Base { public: int concrete() const; virtual int virt() const; }; void benchmark(Base *b, size_t num_iterations) { auto start = Clock::now(); virt_duration = end-start;There are interesting technical details and surprising conclusions that virtual functions can be actually faster. Since CPU architectures are mentioned, I'd expect to see deep nt-vs-inheritance-vs-other- ways-performanceDoes it even matter?Conclusions ● The notion that “virtual functions are slower” is flat out wrong. ○ Which is not to say they are faster ○ Some of the suggested

Hierarchical State Machines The graphical representation of the nodes in a BT has a meaning. Children are ordered from left to right.Are Behavior Trees better than Hierarchical State Machines? HSM BT BT.CPPState CPPState Machines Behavior Trees Learning curve more familiar it needs some practice Concurrency no yes Scalability poor better Readability scales very poorly better Behavior Trees VS Hierarchical Hierarchical State Machines"Tick" and Node types ● The “tick” is the signal that we propagate from the root to the leaves. ● The leaves of the tree are the Actions. I.e. the user-defined code that should be

. . . . . . . . . . . . . 16 1.7 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.8 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 1.10 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.11 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.12 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.13 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . 17 1.7 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.8 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.11 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1.12 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1.13 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1.14 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . 17 1.7 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.8 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1.11 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1.12 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1.13 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1.14 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . 18 1.8 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 19 1.9 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1.12 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.13 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.14 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.15 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . 18 1.8 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 19 1.9 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 1.12 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.13 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.14 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1.15 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

machine settings. Sessions . . . . . . . . . . . . . . . . . . . . . . . . 39 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 7 Host-Guest Communication Manager 285 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 285 7.2 Protocol specification resides the hypervisor – the core of the virtualization engine, con- trolling execution of the virtual machines and making sure they do not conflict with each other or whatever the host computer is doing

machine settings. Sessions . . . . . . . . . . . . . . . . . . . . . . . . 39 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . . . 314 15 Contents 7 Host-Guest Communication Manager 315 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 315 7.2 Protocol specification resides the hypervisor – the core of the virtualization engine, con- trolling execution of the virtual machines and making sure they do not conflict with each other or whatever the host computer is doing