VC++中函数返回对象值的优化实现方式

C 的函数在返回一个非引用类型的值时，一般会将被返回的变量通过复制的方式传递到调用它的上层代码的变量中；但在Visual C 中，当一个函数采用非引用方式返回一个对象时，编译器在一定的条件下会进行编译优化，减少或避免对象在内存中的复制操作，提高程序的运行效率。

Compiling optimization in VC++ function returning an object value

In most cases, when a C++ function returns a value without using reference technology, the value is passed to the calling level variable by copying in memory. However, in Visual C++ and under certain conditions, the compiler will optimize a function returning an object value without using reference technology. The optimization can reduce or avoid copying of the object, so the executing efficiency of the program gets improved.