Operators : _Alignof

Question

_Alignof

Version ≥ C11

Answer 1

Queries the alignment requirement for the specified type. The alignment requirement is a positive integral power of 2 representing the number of bytes between which two objects of the type may be allocated. In C, the alignment requirement is measured in size_t.

The type name may not be an incomplete type nor a function type. If an array is used as the type, the type of the array element is used.

This operator is often accessed through the convenience macro alignof from <stdalign.h>.

int main(void) 

{    

printf("Alignment of char = %zu\n", alignof(char));    

printf("Alignment of max_align_t = %zu\n", alignof(max_align_t));    

printf("alignof(float[10]) = %zu\n", alignof(float[10]));    

printf("alignof(struct{char c; int n;}) = %zu\n", alignof(struct {char c; int n;}));    

}

Possible Output:

Alignment of char = 1 

Alignment of max_align_t = 16 

alignof(float[10]) = 4 

alignof(struct{char c; int n;}) = 4