Re: question re semantics of Ada length clause

[jbg@sei.cmu.edu (John Goodenough)]

The following approved AI specifies answers to some of your questions.
Regarding warning messages, the Standard does not require them, but an
implementation is allowed to provide them.

John B. Goodenough					Goodenough@sei.cmu.edu
Software Engineering Institute				412-268-6391

!standard 13.02    (08)                                 90-07-06  AI-00558/03
!class binding interpretation 88-04-26
!status WG9-approved 90-06-15
!status ARG-approved (10+1-1-1) 89-10-25 (by ballot)
!status ARG-approved (9-0-1) 89-02-27 (pending letter ballot)
!status work-item 88-04-26
!topic Specifying a collection size

!summary 89-11-14

A collection size specification cannot be rejected at compile time just
because the specified collection size is too large.  If insufficient space
is available, STORAGE_ERROR must be raised when elaborating the length
clause. 

If a positive storage size is specified, an implementation must allocate at
least the specified amount of space; reasonable "rounding up" of the
specified amount is allowed, where reasonable is to be understood in terms
of the implementation's usual algorithm for allocating space.  The rounding
algorithm must be specified in Appendix F. 

No space beyond the initial allocation can be provided by an
implementation. If an attempted allocation of a designated object would
exceed the amount of remaining unallocated space, an implementation must
raise STORAGE_ERROR. 

If the specified storage size is zero or negative, no storage is reserved
for the collection.   

-- 
John B. Goodenough					Goodenough@sei.cmu.edu
Software Engineering Institute				412-268-6391