C struct allignment.

main.c

#include <stdio.h>
#include <stddef.h>

struct foo {
	short a;
	int b;
	char c;
};

int main(void) {
	printf("sizeof(short) is %d\n", sizeof(short));
	printf("sizeof(int) is %d\n", sizeof(int));
	printf("sizeof(char) is %d\n\n", sizeof(char));
	
	printf("sizeof(foo) is %d\n\n", sizeof(struct foo));
	
	printf ("offsetof(struct foo,a) is %d\n",(int)offsetof(struct foo,a));
	printf ("offsetof(struct foo,b) is %d\n",(int)offsetof(struct foo,b));
	printf ("offsetof(struct foo,c) is %d\n",(int)offsetof(struct foo,c));
  
	return 0;
}

Output:
sizeof(short) is 2
sizeof(int) is 4
sizeof(char) is 1

sizeof(foo) is 12

offsetof(struct foo,a) is 0
offsetof(struct foo,b) is 4
offsetof(struct foo,c) is 8