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Re: How to compile several C files

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BartC <bc@freeuk.com> writes:

> On 08/02/2017 12:12, Ben Bacarisse wrote:
>> David Brown <david.brown@hesbynett.no> writes:
>
>>> File static data can often be extremely useful.  It lets you have
>>> controlled access to the data from a known set of functions (those in
>>> the same file), without having lots of pointers passed around as
>>> function parameters.
>
>> It's all too easy to downplay the role of experience in programming.  I
>> am sure that when you do this you have considered the alternatives and
>> the future direction the project might take.  (Will there be threading
>> one day?  Will you ever want multiple instantiations of this
>> "module"?...)  The trouble comes when it's simply seen as the obvious
>> way for two functions to operate on some data.
>
> Suppose a program uses static file-scope data, the sort that you
> suggest is a bad way of sharing data across functions.
>
> Suppose also that C has nested functions (this is a gcc extension actually).
>
> Now you can choose to wrap one function around the entire
> program. Those file-scope variables now become local variables.
>
> Does this eliminate the problems with how those variables are shared
> across the nested functions, or not?

Yes, usually.  The nested functions are now no longer independent being
local to some larger operation so they can be understood in this more
limited context.

> After all, when you have declarations in nested block scopes, code in
> different inner scopes can share data declared in a common outer
> scope; I'm struggling to see the difference from sharing file-scope
> data.

The problem is not the sharing per-se but the program structure.  If you
can do what you say -- wrap the whole lot up in another function it says
something about the structure.

To keep it concrete, if the old code was a stack with a file-scope array
and push and pop functions, the fact that you can wrap it up in a larger
function make it quite clear that the stack is use din only one place --
this larger function.  That makes answering questions like, is it OK
that there can be only one stack, much simpler to answer.

-- 
Ben.

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How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 06:10 -0800
  Re: How to compile several C files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-02-07 07:02 -0800
  Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-07 16:03 +0100
  Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 15:06 +0000
    Re: How to compile several C files BartC <bc@freeuk.com> - 2017-02-07 15:14 +0000
      Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 16:02 +0000
    Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 15:42 +0000
      Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 16:19 +0000
        Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 16:40 +0000
          Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 17:16 +0000
            Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:19 +0100
        Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 11:51 -0500
      Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:26 -0800
        Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 16:42 +0000
          Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:14 -0800
          Re: How to compile several C files vitale.alla@gmail.com - 2017-02-16 09:49 -0800
      Re: How to compile several C files Ian Collins <ian-news@hotmail.com> - 2017-02-08 17:35 +1300
        Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:28 +0100
          Re: How to compile several C files Ian Collins <ian-news@hotmail.com> - 2017-02-08 22:43 +1300
            Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 11:29 +0100
      Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:14 +0100
  Re: How to compile several C files James Kuyper <jameskuyper@verizon.net> - 2017-02-07 10:07 -0500
    Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 07:56 -0800
      Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:24 -0800
        Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 16:44 +0000
          Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:54 -0800
            Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 12:20 -0500
              Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:05 -0800
                Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 18:27 +0000
                Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 18:40 +0000
                Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 12:22 -0800
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 10:33 +0100
                Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-08 10:25 -0800
      Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 08:58 -0800
      Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 12:07 -0500
        Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 09:14 -0800
          Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 17:21 +0000
            Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:14 -0800
            Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:28 -0800
              Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 18:43 +0000
                Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 10:55 -0800
            Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-07 19:28 +0000
              Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-07 19:51 +0000
              Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 11:25 +0100
                Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-08 12:11 +0000
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 14:58 +0100
                Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-08 14:23 +0000
                Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 07:48 -0800
                Re: How to compile several C files Richard Heathfield <rjh@cpax.org.uk> - 2017-02-08 16:09 +0000
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 17:23 +0100
                Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 15:01 +0000
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 17:22 +0100
                Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-08 09:27 -0800
                Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 09:51 -0800
                Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 21:06 +0000
                Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 13:20 -0800
                Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 21:40 +0000
                Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 13:49 -0800
                Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 23:09 +0000
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 23:25 +0100
                Re: How to compile several C files supercat@casperkitty.com - 2017-02-08 15:17 -0800
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-09 01:17 +0100
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 23:19 +0100
                Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-08 16:44 -0800
                Re: How to compile several C files Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-08 22:32 -0800
                Re: How to compile several C files Robert Wessel <robertwessel2@yahoo.com> - 2017-02-09 04:03 -0600
                Re: How to compile several C files Ian Collins <ian-news@hotmail.com> - 2017-02-10 07:52 +1300
                Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 12:12 +0000
                Re: How to compile several C files BartC <bc@freeuk.com> - 2017-02-08 13:09 +0000
                Re: How to compile several C files Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-02-08 05:14 -0800
                Re: How to compile several C files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-02-08 15:32 +0000
                Re: How to compile several C files David Brown <david.brown@hesbynett.no> - 2017-02-08 15:09 +0100
        Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 09:22 -0800
          Re: How to compile several C files Gareth Owen <gwowen@gmail.com> - 2017-02-07 18:29 +0000
            Re: How to compile several C files bart4858@gmail.com - 2017-02-07 11:05 -0800
            Re: How to compile several C files Keith Thompson <kst-u@mib.org> - 2017-02-07 12:26 -0800
  Re: How to compile several C files Barry Schwarz <schwarzb@dqel.com> - 2017-02-07 08:34 -0800
    Re: How to compile several C files Alla _ <modelling.data@gmail.com> - 2017-02-07 08:57 -0800
      Re: How to compile several C files "James R. Kuyper" <jameskuyper@verizon.net> - 2017-02-07 12:29 -0500
      Re: How to compile several C files Manfred <noname@invalid.add> - 2017-02-07 19:02 +0100

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