Answer Posted / ritesh pal
When you want to call a constructor directly, you use the placement new. Sometimes you have some raw memory that's already been allocated, and you need to construct an object in the memory you have. Operator new's special version placement new allows you to do it.
class Widget
{
public :
Widget(int widgetsize);
...
Widget* Construct_widget_int_buffer(void *buffer,int widgetsize)
{
return new(buffer) Widget(widgetsize);
}
};
This function returns a pointer to a Widget object that's constructed within the buffer passed to the function. Such a function might be useful for applications using shared memory or memory-mapped I/O, because objects in such applications must be placed at specific addresses or in memory allocated by special routines.
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
how to use C++?
What is a terminating character in c++?
Can you explain polymorphism?
Distinguish between a # include and #define.
What causes polymorphism?
Write a function that swaps the values of two integers, using int* as the argument type?
What does ctime() do?
What is the need of a destructor?
Explain pass by value and pass by reference.
Why is main function important?
What are the unique features of C++.
What is a set in c++?
What is a list in c++ stl?
It is possible to build a C++ compiler on top of a C compiler. How would you do this?
c++ program to swap the objects of two different classes
