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Re: software disenchantment

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: software disenchantment
Date 2018-10-11 11:37 +0200
Organization A noiseless patient Spider
Message-ID <ppn5kf$clr$1@dont-email.me> (permalink)
References (13 earlier) <8yuvD.13782$5A2.519@fx25.am4> <g27b6mFjb2cU5@mid.individual.net> <4TuvD.69650$522.16377@fx35.am4> <g27ccqFjb2cU7@mid.individual.net> <32vvD.21117$134.7822@fx03.am4>

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On 11/10/18 00:28, Bart wrote:
> On 10/10/2018 23:22, Ian Collins wrote:
>> On 11/10/18 11:16, Bart wrote:
>>> On 10/10/2018 23:01, Ian Collins wrote:
>>>> On 11/10/18 10:54, Bart wrote:
>>>
>>>>> And compiling from scratch is preferable to incremental compile
>>>>> which is
>>>>> subject to conditions. So new ways of streamlining the process will
>>>>> always be welcome.
>>>>
>>>> No, compiling from scratch isn't preferable to incremental builds.
>>>
>>> Even if both took the same amount of time? (Or both were fast enough to
>>> be insignificant.)
>>
>> That ain't going to happen for big projects.  The C & C++ part of our
>> project (which isn't too big) contains over 2500 source files.
> 
> Would 2500 object files need to be accessed in the course of even an
> incremental build? Or is it clever enough to patch in only the ones that
> have changed?

Do you know what the term "incremental build" means?

A typical setup has a set of rules to say that, for example, file "a.o"
depends on "a.c", "a.h", "b.h" and "c.h", and "b.o" depends on "b.c",
"a.h" and "b.h".  So if you change file "a.c" and rebuild, only "a.o" is
generated - "b.o" does not need to be touched.  But if you change file
"a.h", then both "a.o" and "b.o" get regenerated.

So for any incremental build, usually only a small fraction (typically
just one) of the object files get re-built.

If you have incremental linking, then much of the previous link results
are also kept - if not, then you may have to read all the object files
for the link.

> 
> If all object files do have to be loaded, then that is not so different
> from having to load source files.
> 

You load the object files for linking.  You load source files for two
purposes - one is to automatically generate dependency trees, which is
usually quite a fast operation, and the other is to compile them - often
the slow part of the process.

My biggest projects are a good deal smaller than Ian's in file counts.
Some timings for a project with 113 object files are:

Serial "clean" build: 51s
Parallel "clean" build: 12s
Incremental build for one C file changed: 1.8s

Does that explain why people use incremental builds?

(And I don't care if your compiler can chew through a gazillion lines
per second - it won't do what I need, so its speed is irrelevant.)

> (And a build system done differently, could eliminate explicit object
> files.)
> 

What a great idea - increase build times by a factor of 10 for my
project, and perhaps 100 for one the size of Ian's.

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Thread

software disenchantment Bart <bc@freeuk.com> - 2018-10-06 15:13 +0100
  Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-06 09:54 -0700
  Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-06 10:26 -0700
    Re: software disenchantment fir <profesor.fir@gmail.com> - 2018-10-14 04:26 -0700
  Re: software disenchantment antispam@math.uni.wroc.pl - 2018-10-09 18:20 +0000
    Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-09 11:54 -0700
      Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-09 21:22 +0100
        Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-09 17:47 -0700
          Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 11:28 +0100
            Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 11:38 +0100
              Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-10 05:49 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-10 15:47 +0200
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 09:58 -0400
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-10 14:39 +0000
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-10 09:42 -0700
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 13:18 -0400
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 20:31 +0100
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 17:53 -0500
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 10:06 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 02:34 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 12:03 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 03:59 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 16:56 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 09:02 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 19:39 +0200
                Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-15 19:53 +0000
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-16 03:54 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 20:25 +0200
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 13:16 +0000
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 07:15 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 17:05 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 09:15 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 17:33 +0000
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 19:53 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 17:59 +0100
                Re: software disenchantment nobody@example.org (Scott) - 2018-10-10 16:53 +0000
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 12:45 -0500
                Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-10 11:04 -0700
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 14:22 -0500
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 15:53 -0400
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 09:06 +1300
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 13:21 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-10 20:27 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 22:54 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:01 +1300
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:05 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 23:16 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:22 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 23:28 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:33 +1300
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 11:37 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 11:50 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 14:10 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 05:24 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 15:12 +0200
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 13:13 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 14:44 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 16:38 +0200
                Re: software disenchantment mark.bluemel@gmail.com - 2018-10-11 08:09 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 17:43 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 17:36 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 18:56 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-11 11:54 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 20:09 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 13:10 +0000
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-13 12:57 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 14:27 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 22:03 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 15:56 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 11:30 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 23:34 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-11 16:24 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 01:46 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-11 18:58 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-12 08:50 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 11:12 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 12:55 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 12:10 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 13:29 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 13:06 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 14:30 +0200
                Re: software disenchantment James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-10-12 08:53 -0400
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 15:11 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 13:55 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 15:13 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 16:10 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 15:22 +0000
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-12 09:12 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-13 13:00 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-13 12:52 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-14 08:44 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-13 21:03 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-14 10:13 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-13 23:02 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-13 16:47 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-14 01:05 +0100
                Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-13 18:12 -0700
                Re: software disenchantment Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-10-14 03:05 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-14 20:14 +0200
                Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-14 11:25 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 13:17 +0000
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 13:16 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 14:36 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 14:25 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 15:55 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 15:22 +0000
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-12 08:26 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 15:51 +0000
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-13 13:06 +0200
                Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-15 19:30 +0000
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 12:39 +0200
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-12 08:44 +0200
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 13:01 +0200
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 20:41 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 20:02 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 22:13 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 13:03 -0500
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-11 11:33 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 21:04 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 20:15 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 13:17 +0200
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 13:10 +0000
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 19:22 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 10:58 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 02:37 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 12:06 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 04:00 -0700
                Re: software disenchantment Cecil Bayona <cbayona@cbayona.com> - 2018-10-11 13:03 -0500
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 19:36 +0100
                Re: software disenchantment Cecil Bayona <cbayona@cbayona.com> - 2018-10-11 15:37 -0500
                Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-10 14:01 -0700
        Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 09:02 +1300
      Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-10 19:11 +0000
        Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-10 13:08 -0700
          Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-11 14:52 +0000
            Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 14:58 +0000
            Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 17:19 +0200
              Re: software disenchantment Dan Purgert <dan@djph.net> - 2018-10-12 09:49 +0000
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-13 09:30 +0200
                Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-15 08:53 +0000
                Re: software disenchantment Dan Purgert <dan@djph.net> - 2018-10-15 09:44 +0000
    Re: software disenchantment Jens Stuckelberger <Jens_Stuckelberger@nowhere.net> - 2018-10-10 13:36 +0000
  Re: software disenchantment "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-10-10 13:51 -0700
    Re: software disenchantment nobody@example.org (Scott) - 2018-10-11 01:53 +0000
    Re: software disenchantment Dan Purgert <dan@djph.net> - 2018-10-11 10:20 +0000
    Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 12:53 +0100
      Re: software disenchantment "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-10-11 23:18 -0700

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