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=-0.4 required=5.0 tests=AC_FROM_MANY_DOTS,BAYES_00 autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,92640d662fc31a03 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-05-04 08:56:08 PST Path: newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!isdnet!psinet-france!psiuk-f4!psiuk-p4!uknet!psiuk-n!news.pace.co.uk!nh.pace.co.uk!not-for-mail From: "Marin David Condic" Newsgroups: comp.lang.ada Subject: Re: howto make system calls (newbie question) Date: Fri, 4 May 2001 11:49:09 -0400 Organization: Posted on a server owned by Pace Micro Technology plc Message-ID: <9cuj1n$gsu$1@nh.pace.co.uk> References: <3AF28F9A.6DC3BD90@earthlink.net> NNTP-Posting-Host: 136.170.200.133 X-Trace: nh.pace.co.uk 988991351 17310 136.170.200.133 (4 May 2001 15:49:11 GMT) X-Complaints-To: newsmaster@pace.co.uk NNTP-Posting-Date: 4 May 2001 15:49:11 GMT X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Xref: newsfeed.google.com comp.lang.ada:7160 Date: 2001-05-04T15:49:11+00:00 List-Id: While I'm basically on your side here, Marc, I think it is fair to point out that in Kernighan & Ritchie (I don't have the ANSI C standard in front of me) it says there is a "Standard Library" that, while "not part of the C language proper" is considered to be part of the C environment that a standard implementation of C will provide. In that library, we find which contains a function "system" that one can reasonably expect to be part of a standard C implementation. I would consider this analogous to the Ada appendices that define things like Unbounded_String, etc. The various string packages are not part of the Ada language per se, but are an expected library of things available in Ada if the implementation is conformant with the standard. I see no reason that Ada couldn't provide similar libraries (perhaps optional for implementations where it makes no sense to have them - e.g. embedded machines) for functions like "system" so that calling conventions, etc., were Ada-ish and required no understanding of anything outside Ada to use. (No pragma import stuff, etc.) If it were legal for us mere mortal hackers to extend the package Ada, it might have already been done. (This is how a lot of things crept into C, after all.) Its fair for someone to criticize Ada for not providing the sort of reasonable and customary libraries one gets with lots of other languages. (Where "reasonable and customary" stops is subject to debate, but I'd think some basic OS services ought to fall within scope.) Saying "well you can get there by binding to the C libraries" is a bit of a "me too!!!" syndrome that keeps Ada a follower rather than a leader. Ada has to get out in front of the issue and create its own interfaces or it will forever find itself fighting the "well then why not just use C/C++ and be done with it?" criticism. That's a hard one to win. I like the idea of having Ada include lots of apendices to bind to things in a standard way. A lot of what is in the C libraries Ada doesn't need because it has other ways of getting there, but why not look over the C libraries and provide an Ada standard way of getting the same services? (Not in a slavish "me too!!!" way - do it "The Ada Way" (tm).) A quick scan of K&R-II Appendix B, suggest the following as things Ada provides no immediate alternative to that could be added in some way: system getenv bsearch qsort (Yes, it exists, but should be part of the standard...) (Yeah, you have some of it with exceptions - OS stuff is what I have in mind here - can we have a standard exception (or other mechanism?) for SIGINT, SIGTERM, SIGABRT?) clock asctime ctime gmtime localtime strftime A little thought about other things commonly supplied by most OS's would probably yield a bunch more ideas. Maybe we'd start seeing some posts in Comp.Lang.C(++) to the effect of "I can do XYZ in Ada - how do I do the same thing in C(++)?" and "Why doesn't C(++) provide me with a function/class to do ABC which I can do in Ada so easily?" (Maybe we can start some shill postings? :-) Just an idea.... MDC -- Marin David Condic Senior Software Engineer Pace Micro Technology Americas www.pacemicro.com Enabling the digital revolution e-Mail: marin.condic@pacemicro.com Web: http://www.mcondic.com/ "Marc A. Criley" wrote in message news:3AF28F9A.6DC3BD90@earthlink.net... > > "system" is neither part of C, nor part of Ada, it is an OS function > that uses a C-style calling syntax. > > There's a widespread belief that OS functions, string handling > functions, and so on, are all part of C, which makes C so much more > powerful than languages like Ada. In reality, all those functions are > provided in libraries for which C bindings have merely been provided by > the vendor. The libraries themselves can be written in any programming > language, it is simply that a C-style calling syntax must be provided. > > I've worked on a shared library, completely written in Ada, that is > invoked by C and Ada applications. Even the Ada applications have to > use "pragma Import(C, ...)" to gain access to its functions. (And of > course the library specifies pragma Export for the visible entities.) > > Marc A. Criley > Senior Staff Engineer > Quadrus Corporation > www.quadruscorp.com