reinterpret cast in C++

A reinterpret_cast operator handles conversions between unrelated types.

>>-reinterpret_cast--<--Type-->--(--expression--)--------------><

The reinterpret_cast operator produces a value of a new type that has the same bit pattern as its argument. You cannot cast away a const or volatile qualification. You can explicitly perform the following conversions:

• A pointer to any integral type large enough to hold it
• A value of integral or enumeration type to a pointer
• A pointer to a function to a pointer to a function of a different type
• A pointer to an object to a pointer to an object of a different type
• A pointer to a member to a pointer to a member of a different class or type, if the types of the members are both function types or object types

A null pointer value is converted to the null pointer value of the destination type.

Given an lvalue expression of type T and an object x, the following two conversions are synonymous:

• reinterpret_cast<T&>(x)
• *reinterpret_cast<T*>(&x)

// An example that uses reinterpret_cast.

#include <iostream>

using namespace std;

int main()

{

int i;

char *p = "This is a string";

i = reinterpret_cast<int> (p); // cast pointer to integer

cout << i;

return 0;

}

Here, reinterpret_cast converts the pointer p into an integer. This conversion represents a fundamental type change and is a good use of reinterpret_cast.

Source : Google