While 64-bit C++ code uses the same primitive data types as 32-bit code, the memory footprint of some integral types adjusts to the new 8-byte width. These changes can affect existing 32-bit C++ code extensively. A good understanding of the 64-bit data architecture is essential for successfully porting a 32-bit application.
This section describes differences between 32-bit and 64-bit data types and how you can use polymorphism to write code that works in either environment.