Path: utzoo!attcan!uunet!husc6!think!ames!pasteur!ucbvax!MAILGW.CC.UMICH.EDU!rees
From: rees@MAILGW.CC.UMICH.EDU (Jim Rees)
Newsgroups: comp.sys.apollo
Subject: Re: How does ios_dir_$open work?
Message-ID: <8808171351.AA03612@mailgw.cc.umich.edu>
Date: 16 Aug 88 18:19:24 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: rees@caen.engin.umich.edu (Jim Rees)
Organization: The Internet
Lines: 18


    Yet, you must admit that it seems a little strange that there is this
    call to simplify access to objects across a transparent file access
    mechanism and it does not work with local objects. After all, isn't the
    whole idea of transparent file access supposed to be that the application
    program can't tell whether or not the file is local? In the case of
    the IOS_DIR$OPEN call, the application must know beforehand that the
    object is NOT local!

Transparent interfaces are always built on top of specific
implementations. Ios_dir is intended to be the interface exported by the
manager, not the interface used by applications to achieve transparency.

When I'm writing an application, I don't use ios_dir.  I use opendir(),
chdir(), readdir(), closedir(), etc.  These are the real
manager-independent calls.  Besides which, they give you portability to
other Unix systems that don't have extensible streams.
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