r = (*compar)(key, (*rootp)->key); if (r == 0)			 return *rootp;
r = (*compar) (key, root->key); if (r == 0) return root;
weak_alias (__tsearch, tsearch)void *__tfind (key, vrootp, compar)     const void *key;     const void **vrootp;     __compar_fn_t compar;{  node **rootp = (node **) vrootp;  if (rootp == NULL)    return NULL;  while (*rootp != NULL)		/* Knuth's T1: */    {      int r;      r = (*compar)(key, (*rootp)->key);      if (r == 0)			/* T2: */	return *rootp;			/* we found it! */      rootp = (r < 0)	      ? &(*rootp)->left		/* T3: follow left branch */	      : &(*rootp)->right;	/* T4: follow right branch */    }    return NULL;}