From jls@cray.com Wed Aug 26 00:51:23 1998 Received: from timbuk-fddi.cray.com (timbuk-e1.cray.com [128.162.1.30]) by dkuug.dk (8.8.7/8.8.7) with ESMTP id AAA10960 for ; Wed, 26 Aug 1998 00:51:22 +0200 (CEST) (envelope-from jls@cray.com) Received: from ledzep.cray.com (ledzep.cray.com [137.38.226.97]) by timbuk-fddi.cray.com (8.8.8/CRI-gate-news-1.3) with ESMTP id RAA28208; Tue, 25 Aug 1998 17:44:30 -0500 (CDT) Received: from ironwood-e185.cray.com (root@ironwood-e185.cray.com [128.162.185.212]) by ledzep.cray.com (8.8.8/craymail-smart) with ESMTP id RAA2794823; Tue, 25 Aug 1998 17:44:28 -0500 (CDT) Received: from sequoia (jls@sequoia-fddi [128.162.21.1]) by ironwood-e185.cray.com (8.8.4/CRI-ironwood-news-1.0) with SMTP id RAA09046; Tue, 25 Aug 1998 17:44:28 -0500 (CDT) From: Jon Steidel Received: by sequoia (SMI-8.6/btd-b3) id RAA27029; Tue, 25 Aug 1998 17:44:26 -0500 Message-Id: <199808252244.RAA27029@sequoia.cray.com> Subject: Re: (SC22WG5.1536) String standard, module and F95 To: helbig@man.ac.uk (Phillip Helbig) Date: Tue, 25 Aug 1998 17:44:25 -0500 (CDT) Cc: SC22WG5@dkuug.dk In-Reply-To: <199808231731.TAA00333@dkuug.dk> from "Phillip Helbig" at Aug 23, 98 04:06:49 pm X-Mailer: ELM [version 2.4 PL24-CRI-b] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit > j.l.schonfelder@liverpool.ac.uk wrote: > > > I may be naive but I > > have always thought automatic objects built on the stack were more efficient > > that allocatable ones built on the heap. > > Is the assumption automatic=stack and allocatable=heap always valid, > i.e. is this what all compilers (must) do? > This is not always the case. Some implementations use a fragmented stack (one run out of the heap which may be non-contiguous). Upon entry to a routine, a check may be made to see if there is enough space in the current stack frame for automatics, if so they go to the stack, otherwise the heap (this avoids system overhead to mangage stack expansion bookkeepping). jon