The Max_Size_In_Storage_Elements and Max_Alignment_For_Allocation 
attributes may be useful in writing user-defined pool types. 
Denotes the maximum value for 
Size_In_Storage_Elements that could be requested by the implementation 
via Allocate for an access type whose designated subtype is S. The value 
of this attribute is of type 
universal_integer. 
 
Denotes the maximum value for 
Alignment that could be requested by the implementation via Allocate 
for an access type whose designated subtype is S. The value of this attribute 
is of type 
universal_integer. 
 
For a type with access discriminants, if the implementation 
allocates space for a coextension in the same pool as that of the object 
having the access discriminant, then these attributes account for any 
calls on Allocate that could be performed to provide space for such coextensions.