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Re: Compiling and linking code from different places in the file system

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Compiling and linking code from different places in the file system
Date 2018-03-12 17:06 +0100
Organization A noiseless patient Spider
Message-ID <p868iu$ci2$1@dont-email.me> (permalink)
References (16 earlier) <748d0aaa-e82a-4437-b6bd-f70e69c82904@googlegroups.com> <p7tid4$fmm$1@dont-email.me> <601fd63c-4613-4892-9dd6-8fe8cc61c043@googlegroups.com> <p811oc$jah$1@dont-email.me> <ad0acdef-60f4-4a7c-ad5c-cfea269b88a0@googlegroups.com>

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On 12/03/18 16:26, supercat@casperkitty.com wrote:
> On Saturday, March 10, 2018 at 10:39:48 AM UTC-6, David Brown wrote:
>> On 09/03/18 19:33, supercat@casperkitty.com wrote:
>>> True.  I would suggest that designers of implementations should recognize
>>> the value of configuration options to support code written for earlier
>>> implementations.  I am rather disappointed that C implementations have not
>>> done a better job of allowing modules which have different expectations
>>> with regard to integer size to be linked together if all interfaces between
>>> them use fixed-size types.
>>
>> That seems a /very/ obscure need.  The only platform I can think of 
>> where it was common to use different sizes of "int" was the early 68k 
>> processors, where people sometimes chose to use 16-bit for speed. 
>> Compilers for these devices sometimes had command-line options to choose 
>> 16-bit or 32-bit ints.
> 
> Using 16-bit "int" would have also allowed for compatibility with code
> written for other platforms like the 6809 where "int" was 16 bits.  If
> compatibility with existing code weren't a consideration, many of the
> more troublesome parts of C syntax could have been cleaned up long ago.
> The fact that they haven't suggests that compatibility is seen as
> important.

The code would have been source-code compatible anyway - as long as
people don't make silly, unnecessary and invalid assumptions about sizes
without checking them.  And the code would never have been object code
compatible.

> 
>>> That's true when writing entirely-new code.  When adapting existing code,
>>> things are less clear-cut, especially if parts of it cannot be modified.
>>
>> If you have existing code that cannot be modified, and it makes invalid 
>> assumptions that don't apply on your current target, then you can't use 
>> it.  It is that simple.
> 
> So it would be impossible for a compiler targeting x64 to successfully
> process code that expects "long" to be 32 bits?  Maybe someone should tell
> Microsoft that.
> 

If code has been written using silly and unnecessary assumptions about
sizes (like a lot of DOS and Windows C code), then you can keep it
working by keeping these assumptions valid in other compilers.  This is,
I think, the reason why MS decided that long should be 32-bit on 64-bit
Windows - it was to reduce the amount of bad code that would have to be
changed by incompetent programmers who never understood how to write
portable C.  (This was not helped by MS' inability to make a C99 compiler.)

Of course, this did not help for code that had other silly, unnecessary
and invalid assumptions that Windows programmers liked to make - such as
that pointers can fit in a "long".  It seems that MS felt that this was
less common than the mistake of assuming "long" was 32-bit, and so that
was the size they picked for "long".  This is despite MS having a long
history of typedef's and macros for particular sized types.

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Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-01 14:40 +0000
  Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-01 14:55 +0000
    Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-02 21:05 +0000
      Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-03 01:18 +0000
        Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-09 01:03 +0000
      Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-02 22:37 -0800
      Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-09 01:23 +0000
  Re: Compiling and linking code from different places in the file system "James R. Kuyper" <jameskuyper@verizon.net> - 2018-03-01 11:11 -0500
    Re: Compiling and linking code from different places in the file system "James R. Kuyper" <jameskuyper@verizon.net> - 2018-03-01 13:51 -0500
      Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-01 11:02 -0800
    Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-03 09:48 +0000
      Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-03 04:06 -0800
        Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-03 05:24 -0800
          Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-03 06:43 -0800
    Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-06 13:51 -0800
  Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-01 22:46 +0000
    Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-01 15:27 -0800
    Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-03 12:25 +0000
      Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-03 04:53 -0800
      Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-03 15:32 +0000
        Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-03 08:02 -0800
        Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-04 07:52 +0000
        Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-04 08:43 +0000
          Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-05 07:58 +0000
            Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-06 21:37 +0000
              Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-07 21:02 +0000
          Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-05 15:29 +0000
            Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-07 04:54 +0000
              Re: Compiling and linking code from different places in the file system Robert Wessel <robertwessel2@yahoo.com> - 2018-03-07 00:33 -0600
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-07 09:55 +0000
      Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-04 07:39 +0000
        Re: Compiling and linking code from different places in the file system Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-03-07 05:00 -0800
          Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-07 14:09 +0000
            Re: Compiling and linking code from different places in the file system Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-03-07 14:26 +0000
              Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-07 16:35 +0000
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-07 09:32 -0800
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-07 10:11 -0800
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-07 11:12 -0800
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-07 12:01 -0800
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-07 15:43 -0800
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-07 19:18 -0800
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-08 09:59 -0800
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-08 10:28 -0800
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-08 13:36 -0800
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-08 21:47 +0000
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-08 15:03 -0800
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-09 09:59 +0100
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-09 10:33 -0800
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-09 12:27 -0800
                Re: Compiling and linking code from different places in the file system scott@slp53.sl.home (Scott Lurndal) - 2018-03-09 20:48 +0000
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-09 13:31 -0800
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-10 18:31 +0100
                Re: Compiling and linking code from different places in the file system Robert Wessel <robertwessel2@yahoo.com> - 2018-03-10 13:22 -0600
                Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-10 19:15 +0000
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-09 13:28 -0800
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-09 14:13 -0800
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-09 14:45 -0800
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-10 17:39 +0100
                Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-10 19:00 +0000
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 08:26 -0700
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-12 17:06 +0100
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 10:23 -0700
                Re: Compiling and linking code from different places in the file system scott@slp53.sl.home (Scott Lurndal) - 2018-03-12 18:42 +0000
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 12:20 -0700
                Re: Compiling and linking code from different places in the file system scott@slp53.sl.home (Scott Lurndal) - 2018-03-12 20:27 +0000
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 14:12 -0700
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-13 11:12 +0100
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-12 09:23 -0700
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 10:38 -0700
                Re: Compiling and linking code from different places in the file system David Kleinecke <dkleinecke@gmail.com> - 2018-03-12 11:41 -0700
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 12:10 -0700
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-09 12:09 -0800
                Re: Compiling and linking code from different places in the file system scott@slp53.sl.home (Scott Lurndal) - 2018-03-09 20:46 +0000
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-10 18:35 +0100
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 08:54 -0700
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-13 08:39 +0100
                Re: Compiling and linking code from different places in the file system Tim Rentsch <txr@alumni.caltech.edu> - 2018-03-17 11:03 -0700
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-11 07:37 +0000
                Re: Compiling and linking code from different places in the file system David Kleinecke <dkleinecke@gmail.com> - 2018-03-11 14:22 -0700
                Re: Compiling and linking code from different places in the file system Spiros Bousbouras <spibou@gmail.com> - 2018-03-11 21:48 +0000
                Re: Compiling and linking code from different places in the file system David Kleinecke <dkleinecke@gmail.com> - 2018-03-11 17:50 -0700
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-11 15:54 -0700
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-12 09:38 -0700
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-08 10:48 +0100
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-08 09:58 -0800
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-08 22:03 +0100
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-08 13:55 -0800
                Re: Compiling and linking code from different places in the file system Spiros Bousbouras <spibou@gmail.com> - 2018-03-08 22:38 +0000
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-08 15:03 -0800
                Re: Compiling and linking code from different places in the file system Spiros Bousbouras <spibou@gmail.com> - 2018-03-08 23:15 +0000
                Re: Compiling and linking code from different places in the file system Tim Rentsch <txr@alumni.caltech.edu> - 2018-03-17 10:44 -0700
                Re: Compiling and linking code from different places in the file system Steven Petruzzellis <frelwizzen@gmail.com> - 2018-03-18 03:47 -0700
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-09 10:10 +0100
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-09 10:10 -0800
                Re: Compiling and linking code from different places in the file system jameskuyper@verizon.net - 2018-03-08 14:21 -0800
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-08 15:10 -0800
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-09 10:13 +0100
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-09 10:10 -0800
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-08 10:28 +0100
                Re: Compiling and linking code from different places in the file system supercat@casperkitty.com - 2018-03-08 10:28 -0800
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-08 22:17 +0100
                Re: Compiling and linking code from different places in the file system Keith Thompson <kst-u@mib.org> - 2018-03-08 13:26 -0800
  Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-14 13:39 +0100

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