devxlogo

How to Calculate the Alignment in C++

How to Calculate the Alignment in C++

Use the following class to help calculate the alignment in C++:

template<typename T>class Alignment{    struct Align     {        char align;        T t;    };public:    int alignment()    {         return sizeof(Align) - sizeof(T);    }};

Below are two examples that use the Alignment class. The first one is for the char data type; the second one is for the iostream class from the standard Input/Output streams library:

   Alignment char_type;   std::cout << char_type.alignment() << std::endl;   Alignment

The alignment requirement for a data object is hardware- and compiler-specific parameter. Even on the same machine and with the same compiler, the alignment for the same type can be different depending on compiler-specific options. For example, the following compiler command:

   #pragma pack(2)

will result in many compilers to use at most two-byte alignment for the data that follow the directive (please note that pragma directives cannot increase alignment for a data object).

See also  lenso.ai - an AI reverse image search platform
devxblackblue

About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

About Our Journalist