Re: Differences between C and C++

From	Muttley@dastardlyhq.com
Newsgroups	comp.lang.c++
Subject	Re: Differences between C and C++
Date	2022-07-30 14:23 +0000
Organization	Aioe.org NNTP Server
Message-ID	<tc3et5$ako$1@gioia.aioe.org> (permalink)
References	(12 earlier) <0e86f6a1-49e3-43d6-9a06-f229d5218568n@googlegroups.com> <tc0vgm$qp6$1@gioia.aioe.org> <1169aff2-c762-4756-aeb4-dc6c35806e6fn@googlegroups.com> <tc2tjo$1pf4$1@gioia.aioe.org> <6f30371a-356a-4152-9f57-e4362de1dea4n@googlegroups.com>

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On Sat, 30 Jul 2022 03:39:11 -0700 (PDT)
=?UTF-8?B?w5bDtiBUaWli?= <ootiib@hot.ee> wrote:
>On Saturday, 30 July 2022 at 12:28:45 UTC+3, Mut...@dastardlyhq.com wrote:
>> On Fri, 29 Jul 2022 13:12:55 -0700 (PDT)
>> =?UTF-8?B?w5bDtiBUaWli?= <oot...@hot.ee> wrote: 
>> >On Friday, 29 July 2022 at 18:48:55 UTC+3, Mut...@dastardlyhq.com wrote: 
>> >> On Fri, 29 Jul 2022 08:25:21 -0700 (PDT)
>> >> Great idea, put a layer on top, that'll make things more efficient. 
>> >Sometimes 
>> >> things that matter include raw data (if you do systems or low level 
>> >programming 
>> >> which I suspect you don't) and good luck processing that efficiently in 
>> >> std::string. 
>> > 
>> >You suspect wrongly. The effect of most library classes is just that 
>> >those compile to about same code what you would do in C, just look
>> 
>> If there's an interface layer there's a non zero time penalty for going
>through 
>> it.
>
>On majority of cases with actual compilers that claim is incorrect.
>Compilers inline function calls and optimize code not on narrow cases but
>aggressively and massively. The libraries are typically written in manner to
>support it. Naive code can use some construct that makes it hard for
>compiler. Profilers have shown me plenty of that during decades. 

Inlined functions still have code to be executed. You can't get an API
translation layer down to zero instructions if you're converting to complex 
types such as std::string.

>> >easier to read. The hand-written code is commonly less efficient, more 
>> >verbose, more error-prone, harder for compiler to optimize and maintainer 
>> >to fix.
>> Really? Here's some code from a utility I wrote that reads network data into 
>
>> a u_char frame buffer. Feel free to tell us how using std::string or similar 
>
>> would improve the speed or make the code any more readable: 
>
>Odd request. The std::string is meant for processing texts. If someone puts
>some other data into it then they make their life harder, not easier.   

Not something that occured to you when you were asking what the point of
char* was.

>
>> 
>> switch((rlen = read(bpf_fd,frame_buffer,frame_buffsize))) 
>> { 
>> case 0: 
>> assert(0); 
>
>That asserts that there are never end of file?

Its reading a berkeley packet filter intercepting UDP packets which has got to 
this point via select() first. If read() returns 0 at this point then something
is fucked inside the API or OS.

>> case -1: 
>> perror("ERROR: read()"); 
>> exit(1); 
>
>Any error ends the program? 

Yes, because it can't progress. Its a client, not a server.

>Further code assumes that all read packets fit to buffer. I don't have such
>code
>What embedded device it is that dies down on usual situations? Speed or
>readability matter only after it is useful.

Point proven I think.

Thread

Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-25 13:14 +0000
  Re: Differences between C and C++ "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-07-25 16:18 +0200
  Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-25 18:47 +0300
    Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-25 19:49 +0300
      Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-25 19:38 +0100
  Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-25 08:51 -0700
  Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-25 17:14 +0100
    Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-25 16:19 +0000
      Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-25 19:28 +0100
      Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-25 12:21 -0700
        Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-26 07:54 +0000
          Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 08:00 +0000
            Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-26 08:09 +0000
              Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-26 02:42 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-26 15:29 +0000
                Re: Differences between C and C++ scott@slp53.sl.home (Scott Lurndal) - 2022-07-26 16:30 +0000
                Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-26 11:59 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-27 07:52 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-27 01:56 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-27 14:51 +0000
                Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-27 11:11 -0700
    Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 06:09 +0000
      Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-27 17:33 +0100
  Re: Differences between C and C++ Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-07-25 17:45 +0100
  Re: Differences between C and C++ Paul N <gw7rib@aol.com> - 2022-07-27 10:09 -0700
    Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-07-27 19:28 +0200
      Re: Differences between C and C++ Paul N <gw7rib@aol.com> - 2022-07-27 11:43 -0700
        Re: Differences between C and C++ David Brown <david.brown@hesbynett.no> - 2022-07-29 18:04 +0200
          Re: Differences between C and C++ Richard Damon <Richard@Damon-Family.org> - 2022-07-29 18:47 -0400
            Re: Differences between C and C++ David Brown <david.brown@hesbynett.no> - 2022-07-30 14:08 +0200
      Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-28 08:03 +0000
        Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-28 01:57 -0700
          Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-28 09:04 +0000
    Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-28 06:53 +0000
      Re: Differences between C and C++ Richard Damon <Richard@Damon-Family.org> - 2022-07-28 07:33 -0400
        Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-07-28 15:04 +0200
          Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-28 15:11 +0000
            Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-28 20:03 +0300
              Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-29 07:56 +0000
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-29 12:03 +0300
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 09:28 +0000
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-29 12:27 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 05:43 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 14:14 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 08:25 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 15:48 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 13:12 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-30 09:28 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-30 03:39 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-30 14:23 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-30 19:07 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-31 07:22 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-31 06:07 -0700
                Re: Differences between C and C++ muttley@dastardlyhq.com - 2022-07-31 16:36 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-08-01 01:12 -0700
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-29 22:47 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-30 03:48 -0700
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 05:16 -0700
                Re: Differences between C and C++ Manfred <noname@add.invalid> - 2022-07-30 02:14 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-31 14:39 +0000
                Re: Differences between C and C++ "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2022-07-31 18:49 +0200
                Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-07-31 14:49 -0700
                Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-31 17:03 -0700
                Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-01 00:16 -0700
                Re: Differences between C and C++ Ike Naar <ike@sdf.org> - 2022-08-01 07:27 +0000
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-01 10:47 +0300
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-01 10:34 +0300
                Re: Differences between C and C++ Manfred <noname@add.invalid> - 2022-08-03 01:20 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-03 07:59 +0000
                Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-08-03 12:45 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-03 10:53 +0000
                Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-03 03:58 -0700
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-03 14:49 +0300
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-08-03 23:31 -0700
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-01 11:29 +0000
                Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-08-01 14:39 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-02 05:43 +0000
                Re: Differences between C and C++ Manfred <noname@add.invalid> - 2022-08-03 01:13 +0200
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-03 09:34 +0300
              Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 09:22 +0000
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-29 13:53 +0300
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-29 14:13 +0300
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 14:11 +0000
        Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-07-28 06:16 -0700

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