NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/comp/lang/fortran/4836

Text File | 1992-12-22 | 1.8 KB | 45 lines

Newsgroups: comp.lang.fortran
Path: sparky!uunet!timbuk.cray.com!walter.cray.com!craywr!wws
From: [e-mail] (Walter Spector)
Subject: Re: Dynamic Memory Allocation in FORTRAN, Question
Message-ID: <[e-mail]>
Lines: 32
Sender: wws@craywr (Walter Spector)
Nntp-Posting-Host: craywr.cray.com
Organization: Cray Research, Inc.
References: <[e-mail]>
Date: 22 Dec 92 13:35:59 CST

In article <[e-mail]>, [e-mail] (Xiong) writes:
|> Hi, I am wondering if it is possible to allocate memory dynomically in
|> FORTRAN as in C?

There are no Standard mechanisms in the Fortran-77 Standard for performing
dynamic memory management.  Standard non-Standard ways of doing it usually
involve overindexing blank common or some form of pointers combined with
with a sbrk(2)-like or malloc(3c)-like interface.  Performing your own
sbrk system calls is obviously dangerous in a Unix-like environment,
calling a malloc-like routine is more reliable.

In a compiler with Fortran-90 memory management, there are two Standard
options: Automatic arrays which are very nice for scratch arrays,
and ALLOCATABLE variables combined with the ALLOCATE/DEALLOCATE statements
which give a more general capability.  (Note that in Fortran-90, pointers
would generally not be used for memory management.)  Compilers exist which
support one or both of these facilities.

Your compiler system will probably support one or more of the above
techniques.  RTFM for more details.

|> Thanks a lot for your help. If this question has been asked before (I
|> did not find it in the FAQ)

This really is a FAQ and should be included.  Keith?

Walt
----
Walt Spector
([e-mail])
Sunnyvale, California
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