container_of_example.c

struct foo {
  int data1;
  char *data2;
  mytype_t mymember;
  int data3;
};

...

struct foo blah;
mytype_t *var = &(blah.mymember);
container_of(var, struct foo, mymember); /* returns pointer to blah */

...

/* more "practical" example of how this is used in the wild. pretend
   somefunc returns a mytype_t pointer */
struct foo *blah = container_of(somefunc(), struct foo, mymember);