From j.l.schonfelder@liverpool.ac.uk Thu Mar 30 14:31:44 2000 Received: from mailhub1.liv.ac.uk (mailhub1.liv.ac.uk [138.253.100.94]) by dkuug.dk (8.9.2/8.9.2) with ESMTP id OAA25927 for ; Thu, 30 Mar 2000 14:31:41 +0200 (CEST) (envelope-from j.l.schonfelder@liverpool.ac.uk) Received: from pcmail2.liv.ac.uk ([138.253.252.15]) by mailhub1.liv.ac.uk with esmtp (Exim 2.12 #1) id 12ae6r-0006Te-00 for SC22WG5@dkuug.dk; Thu, 30 Mar 2000 12:31:37 +0000 Received: from [138.253.102.118] (helo=pc102118.liv.ac.uk) by pcmail2.liv.ac.uk with smtp (Exim 2.12 #1) id 12ae6p-0005S3-00 for SC22WG5@dkuug.dk; Thu, 30 Mar 2000 13:31:36 +0100 From: Lawrie Schonfelder Reply-To: j.l.schonfelder@liverpool.ac.uk To: SC22/WG5 members Subject: Semantics of the SIZE intrinsic Message-ID: Date: Thu, 30 Mar 2000 13:31:35 +0100 (GMT Daylight Time) Priority: NORMAL X-Mailer: Simeon for Win32 Version 4.1.5 Build (43) X-Authentication: IMSP MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=US-ASCII I have just run into a difficulty with the SIZE intrinsic. As currently defined it is illegal to call it with a disassociated pointer to an array. However, there is no way that I know of to initialise such a pointer to anything other the NULL(). This means that safe procedures cannot be easily written that depend on local working variables whose size is a function of such a pointer argument. This is a common requirement. Many compilers very sensibly extend the definition to allow disassociated pointers to arrays and deallocated allocatable arrays as arguments and return the obvious zero result. One at least appears in checking mode to abort the program and in non-checking mode to return some arbitrary value. Could we not have a minor extension to the standard and define the SIZE intrinsic to return zero in such cases. The alternative would be to provide some way of allowing a pointer to be initialised to have a zero sized array target and likewise an allocatable array to a zero sized array instead of deallocated. In fact I would like both but I would settle for the extended SIZE definition. -- Lawrie Schonfelder Director, Computing Services Dept. The University of Liverpool, UK, L69 7ZF Phone: 44(151)794 3716, Fax: 44(151)794 3759