http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47024
--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> 2010-12-20 16:47:56 UTC --- (In reply to comment #2) > I don't really understand this. Why should one allow it for unallocated > allocatables, but not for undefined pointers? Well, the situation for an unassociated pointer and for an unallocated allocatable is the same: You know that it does not have a dynamic type -- and you can check for this state via "<array>.data == NULL" or "<scalar> == NULL". In case of an undefined pointer, you cannot. Thus, not allowing undefined pointers anywhere makes sense. The initially proposed wording was did not allow for notallocated allocatables/notassociated pointers (http://www.j3-fortran.org/doc/year/06/06-166.txt) but during the meeting 176 meeting the wording of 06-166 was changed (in two revisions, r1 and r2) to what we have today; cf. http://www.j3-fortran.org/doc/meeting/176/06-166r2.txt. Unfortunately, the new version does not clearly tell what the result value should be in that case. Possible choices would be: (a) storage size of the declared type or (b) "zero" or the size of the class container. If (b) is the correct answer, I do not see the reason for the additional restrictions for types with "deferred type parameters" and for "unlimited polymorphic" - one could simply return the same as for an unallocated polymorphic. Thus, I assume that (a) is meant, but I do not see how one can read this from the standard (as opposed to guessing it). Let's see what the J3 members think how it should be interpreted; I think ultimately an interpretation request is required.
