As a result, proxy can largely replace the existing “virtual mechanism” to implement your vision in runtime polymorphism, while having no intrusion on existing code, with even better performance. All the facilities of the library are defined in namespace pro. The 3 major class templates are ...
//building : cl -GR typeid.cpp#include <iostream.h>#include<typeinfo.h>classB//base class, polymorphic.{public:virtualvoidfunc() { };int_data1; };classD :publicB//derived class, polymorphic too.{public:virtualvoidfunc() { };int_data2; }; 现在让我们看一下执行结果,变化出现在polymorp...
If a function is declared asvirtualin the base class, it will be virtual in all its derived classes. The address of the virtual Function is placed in theVTABLEand the copiler usesVPTR(vpointer) to point to the Virtual Function.
you should also remove the /GX compiler flag (the "Enable exception handling" checkbox in the C/C++ options tab), since many libraries (including the STL implementation that ships with Visual C++) discriminate their functionality via the preprocessor symbol _CPPUNWIND, inserting exception-...
That means you don't waste time optimising things which are nowhere near the critical path. It also means (and this is very important), that you have a known working program to benchmark against (both in terms of features and performance). If your latest hack breaks the program (or makes...
Runtime polymorphism usually connects with v-tables and virtual functions. However, in this blog post, I’ll show you a modern C++ technique that leverages std::variant and std::visit. This C++17 technique might offer not only better performance and value semantics but also interesting design ...