*Defined in /sys/composite.h

/*
 *
 * Function:    composite
 * Description: Creates a composite description of objects
 * Arguments:   x:          Array of the objects to describe
 *              sf:         Function to call in objects to get its <name>
 *                          Objects with the same <names> are described
 *                          together.
 *              df:         Function to call to get the actual description of
 *                          a group of 'same objects' i.e objects whose
 *                          'sf' returned the same value.
 *              ob:         Object to call df in.
 *
 *              for_ob:     Who want this description?
 *
 * Returns:     A description string on the format:
 *              <desc>, <desc> and <desc>
 *              Where <desc> is what ob->df() returns
 *
*/
#define COMPOSITE(x, sf, df, ob) \
  (string) call_other(COMPOSITE_FILE, "composite", x, sf, df, ob)

