bitfield.c

struct Struct1 {

        unsigned int a0;
        unsigned int a1;
        unsigned int a2;
        unsigned int a3;
};


struct Struct2 {

        unsigned int a0 : 1;
        unsigned int a1 : 1;
        unsigned int a2 : 2;
        unsigned int a3 : 4;

};

struct Struct3 {

        unsigned int a0 : 1;
        unsigned int a1 : 1;
        unsigned int a2 : 2;
        unsigned int a3 : 4;

} __attribute__((__packed__));

int main(int argc, char *argv[]) {
	struct Struct1 a; /* sizeof(a) = 16 bytes */
	struct Struct2 b; /* sizeof(b) = 4  bytes */
	struct Struct3 c; /* sizeof(c) = 1  byte  */
	return 0;
}