Re: reasons for preferring C over C++

From	Niklas Holsti <niklas.holsti@tidorum.invalid>
Newsgroups	comp.arch.embedded
Subject	Re: reasons for preferring C over C++
Date	2014-10-19 11:03 +0300
Organization	Tidorum Ltd
Message-ID	<cah9jeFop0nU1@mid.individual.net> (permalink)
References	(1 earlier) <m1mmar.23s.1@stefan.msgid.phost.de> <caf18hF6lueU1@mid.individual.net> <7x4mv1tdyv.fsf@ruckus.brouhaha.com> <VUA0w.496001$_u1.143324@fx30.am4> <7x8ukd9f0c.fsf@ruckus.brouhaha.com>

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On 14-10-19 01:42 , Paul Rubin wrote:
> Tom Gardner <spamjunk@blueyonder.co.uk> writes:
>>> use containers of multiple types without having to paste code all
>>> over the place.
>> but although /you/ don't have to make duplications in the
>> source code, doesn't the /compiler/ have to expand them in
>> the object code.
> 
> C++ templates do work like that, so you indeed get bloat in the object
> code (just as if you'd manually duplicated code like you'd have to in
> C), but the source code becomes more uniform and maintainable.  The
> bloat isn't a law of nature but rather reflects C++'s design goal of
> zero-overhead abstraction.  
> 
> Other languages like Haskell can avoid the bloat by supporting
> polymorphic functions implemented by passing type info at runtime,
> taking a slight penalty in speed.  I'm not sure how Ada handles this.
> Ada has generic but I don't know how they work.

The rules for Ada generics are specified so that generic units can
either share code between instances, or can use the "macro" approach and
generate specific code for each instance. Some compilers use shared
code, others use the macro approach. I believe there have been some
compilers that let the programmer choose which method to use, but I
don't know if that can be done in any current compiler.

The GNAT compiler uses the macro approach (specific code for each
instance). This tends to produce faster code, at the cost of more code,
of course.

It is sometimes possible to divide generic Ada units into two parts: a
non-generic part that has most of the complex code, and a small generic
wrapper that contains the code that is duplicated (and separately
optimised) for each instance. One way to do to that is to use
tagged-type polymorphism, similar to the Haskell way.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
      .      @       .

Thread

reasons for preferring C over C++ Wouter van Ooijen <wouter@voti.nl> - 2014-10-15 19:21 +0200
  Re: reasons for preferring C over C++ Paul Rubin <no.email@nospam.invalid> - 2014-10-15 10:36 -0700
    Re: reasons for preferring C over C++ Wouter van Ooijen <wouter@voti.nl> - 2014-10-15 19:48 +0200
      Re: reasons for preferring C over C++ Tom Gardner <spamjunk@blueyonder.co.uk> - 2014-10-15 21:25 +0100
        Re: reasons for preferring C over C++ Wouter van Ooijen <wouter@voti.nl> - 2014-10-15 23:28 +0200
          Re: reasons for preferring C over C++ Tom Gardner <spamjunk@blueyonder.co.uk> - 2014-10-15 23:40 +0100
  Re: reasons for preferring C over C++ Don Y <this@is.not.me.com> - 2014-10-15 10:58 -0700
  Re: reasons for preferring C over C++ upsidedown@downunder.com - 2014-10-15 21:03 +0300
    Re: reasons for preferring C over C++ Don Y <this@is.not.me.com> - 2014-10-15 11:11 -0700
    Re: reasons for preferring C over C++ Wouter van Ooijen <wouter@voti.nl> - 2014-10-15 20:26 +0200
  Re: reasons for preferring C over C++ Stefan Reuther <stefan.news@arcor.de> - 2014-10-15 20:44 +0200
    Re: reasons for preferring C over C++ Wouter van Ooijen <wouter@voti.nl> - 2014-10-15 23:30 +0200
      Re: reasons for preferring C over C++ Stefan Reuther <stefan.news@arcor.de> - 2014-10-16 18:19 +0200
        Re: reasons for preferring C over C++ Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2014-10-16 23:12 +0200
          Re: reasons for preferring C over C++ Reinhardt Behm <rbehm@hushmail.com> - 2014-10-17 13:25 +0800
          Re: reasons for preferring C over C++ Stefan Reuther <stefan.news@arcor.de> - 2014-10-17 18:43 +0200
    Re: reasons for preferring C over C++ "tim....." <tims_new_home@yahoo.co.uk> - 2014-10-18 12:29 +0100
      Re: reasons for preferring C over C++ Paul Rubin <no.email@nospam.invalid> - 2014-10-18 11:44 -0700
        Re: reasons for preferring C over C++ Tom Gardner <spamjunk@blueyonder.co.uk> - 2014-10-18 22:25 +0100
          Re: reasons for preferring C over C++ Paul Rubin <no.email@nospam.invalid> - 2014-10-18 15:42 -0700
            Re: reasons for preferring C over C++ Niklas Holsti <niklas.holsti@tidorum.invalid> - 2014-10-19 11:03 +0300
            Re: reasons for preferring C over C++ Tim Wescott <seemywebsite@myfooter.really> - 2014-10-19 17:46 -0500
              Re: reasons for preferring C over C++ Paul Rubin <no.email@nospam.invalid> - 2014-10-19 16:28 -0700
              Re: reasons for preferring C over C++ Nobody <nobody@nowhere.invalid> - 2014-10-20 02:47 +0100
        Re: reasons for preferring C over C++ "tim....." <tims_new_home@yahoo.co.uk> - 2014-10-19 09:34 +0100
          Re: reasons for preferring C over C++ Paul Rubin <no.email@nospam.invalid> - 2014-10-19 17:00 -0700
            Re: reasons for preferring C over C++ Tom Gardner <spamjunk@blueyonder.co.uk> - 2014-10-20 08:50 +0100
              Re: reasons for preferring C over C++ "tim....." <tims_new_home@yahoo.co.uk> - 2014-10-20 11:57 +0100
                Re: reasons for preferring C over C++ Tom Gardner <spamjunk@blueyonder.co.uk> - 2014-10-20 12:11 +0100
                Re: reasons for preferring C over C++ upsidedown@downunder.com - 2014-10-20 22:36 +0300
                Re: reasons for preferring C over C++ Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> - 2014-10-21 00:36 +0000
            Re: reasons for preferring C over C++ Tom Gardner <spamjunk@blueyonder.co.uk> - 2014-10-20 08:52 +0100
            Re: reasons for preferring C over C++ "tim....." <tims_new_home@yahoo.co.uk> - 2014-10-20 11:56 +0100
        Re: reasons for preferring C over C++ Stefan Reuther <stefan.news@arcor.de> - 2014-10-19 10:52 +0200
          Re: reasons for preferring C over C++ Paul Rubin <no.email@nospam.invalid> - 2014-10-19 17:16 -0700
      Re: reasons for preferring C over C++ glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-10-18 23:02 +0000
        Re: reasons for preferring C over C++ "tim....." <tims_new_home@yahoo.co.uk> - 2014-10-19 09:45 +0100
  Re: reasons for preferring C over C++ David Brown <david.brown@hesbynett.no> - 2014-10-15 22:12 +0200
    Re: reasons for preferring C over C++ Wouter van Ooijen <wouter@voti.nl> - 2014-10-15 23:35 +0200
      Re: reasons for preferring C over C++ Paul Rubin <no.email@nospam.invalid> - 2014-10-15 19:10 -0700
      Re: reasons for preferring C over C++ Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2014-10-16 10:34 +0300
        Re: reasons for preferring C over C++ Tom Gardner <spamjunk@blueyonder.co.uk> - 2014-10-16 10:10 +0100
  Re: reasons for preferring C over C++ Tim Wescott <tim@seemywebsite.com> - 2014-10-16 01:06 -0500
  Re: reasons for preferring C over C++ Anders.Montonen@kapsi.spam.stop.fi.invalid - 2014-10-16 08:32 +0000
    Re: reasons for preferring C over C++ David Brown <david.brown@hesbynett.no> - 2014-10-16 20:54 +0200

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