char *p1 = alloc();
if (p1 == NULL) goto ERROR;

char *p2 = alloc();
if (p2 == NULL) goto ERROR2;

char *p3 = alloc();
if (p3 == NULL) goto ERROR3;

...

return 1;

ERROR3: free(p2);
ERROR2: free(p1);
ERROR:  return 0