From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=BAYES_00,INVALID_DATE autolearn=no autolearn_force=no version=3.4.4 Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.ARPA Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!eglin-vax.arpa!harbaughs From: harbaughs@EGLIN-VAX.ARPA Newsgroups: net.lang.ada Subject: Text_IO concurrency Message-ID: <8509182010.AB00607@UCB-VAX.ARPA> Date: Wed, 18-Sep-85 11:11:47 EDT Article-I.D.: UCB-VAX.8509182010.AB00607 Posted: Wed Sep 18 11:11:47 1985 Date-Received: Fri, 20-Sep-85 05:02:58 EDT Sender: daemon@ucbvax.ARPA Organization: The ARPA Internet List-Id: 18 Sep 1985 How could i pass up Dave Bakin's invitation to speak up. I haven't heard from John Goodenough on this yet so i'll jump the gun and put it out for all to see, shoot at etc. -- Date: Mon, 09 Sep 85 11:50:13 CDT From: harbaughs@EGLIN-VAX Subject: Ada difficulties per your request To: goodenough@usc-isi Cc: harbaughs@eglin-vax John, -- You decide if this is aprpro to put out on info-ada. -- The part of Ada that continuously gives me and others a hard time is text_io. Last Friday 3 of us wasted an hour until we concluded that text_io is a single thread package and cannot support simultaneous calls to get and put (one in each of two tasks). In the recent past I have had difficulty with while loops which look for EOF and doing a get in the loop. -- I think that text_io qualifies for your request of Ada things that draw the programmer into erroneous programs because the implementations of text_io don't seem to follow the simple explanation in the LRM. Either the LRM doesn't begin to explain what the validators will accept or the validation doesn't check what the LRM says or a bit of both. -- Philosophically, it is always the interfaces to other systems that are the biggest difficulty in system design and text_io is an example of interfacing the Ada language to (in my case) the VAX VMS and the terminal handler and the VT100. -- If text_io is intended to be single thread then perhaps it should be speced as a task so that it is clear that only a get or a put will be accepted and processed but not both at the same time. -- regards,sam harbaugh --------------------