All C++ programs must have a `main` function. If you try to compile a C++ *.exe* project without a main function, the compiler will raise an error. Dynamic-link libraries and static libraries don't have a `main` function. Although `main` is the starting point of execution, but before a program enters the `main` function, all static class members without explicit initializers are set to zero. In Microsoft C++, global static objects are also initialized before entry to `main`. Several restrictions apply to the `main` function that do not apply to any other C++ functions. The `main` function: