30. Alignment <stdalign.h>

The header <stdalign.h> defines four macros.

The macro

alignas

expands to _Alignas; the macro

alignof

expands to _Alignof.

The remaining macros are suitable for use in #if preprocessing directives. They are

__alignas_is_defined

and

__alignof_is_defined

which both expand to the integer constant 1.