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Re: Global const objects missing from object file

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scott@slp53.sl.home (Scott Lurndal) writes:

> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>
>> Paavo Helde <myfirstname@osa.pri.ee> writes:
>>
>>> In some sense the do not differ.  The const globals in C++ are
>>> primarily meant for replacing C #define.  Each C #define is TU-specific
>>> and gets fully preprocessed by the preprocessor, no other TU-s are
>>> involved.
>>
>> It appears you have sidestepped the central question here.  What a
>> definition like 'const int foo = 7;'  (without any mention anywhere
>> of 'extern') does in C++ is, AFAICT, exactly the same as a similar
>> definition with static, namely 'static const int foo = 7;'.
>
> Is that not dependent upon scope?  For example:
>
> class x {
>   static const unsigned long FRED = 0xabcdef00ul;
>
> };

Yes, it's true that leaving off 'static' here means something
significantly different.  Note however, (a) neither of these
forms is allowed in C so there is no question of incompatibility;
(b) the 'static'-less form wasn't allowed until C++11;  (c) only
the 'static' form works for the purpose of being usable in
constant expressions, so the question here is moot.

> requires an additional declaration in a compilation unit, e.g.
>
>   const unsigned long x::FRED;

In my tests such a declaration was needed only if the address of
the static member FRED was taken.  (I confess I didn't even try
to consult the C++ standard to see if that result is officially
okay or is merely a consequence of undefined behavior.)

> While
>
> namespace y {
>    const unsigned long FRED = 0xabcdef00ul;
> };
>
> doesn't require an additional declaration.

AFAICT declarations inside namespaces behave the same way as
declarations at file scope, that is, const-without-static
behaves just the same way as const-with-static (and the same
rules for declarations/definitions, etc).  So I don't think
this scenario is an exception to what I said earlier.

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Thread

Global const objects missing from object file Steve Keller <keller.steve@gmx.de> - 2021-10-08 22:47 +0200
  Re: Global const objects missing from object file red floyd <no.spam.here@its.invalid> - 2021-10-08 15:09 -0700
    Re: Global const objects missing from object file Steve Keller <keller.steve@gmx.de> - 2021-10-10 08:28 +0200
      Re: Global const objects missing from object file Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-10 12:03 +0300
      Re: Global const objects missing from object file David Brown <david.brown@hesbynett.no> - 2021-10-10 12:29 +0200
  Re: Global const objects missing from object file Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-09 10:47 +0300
    Re: Global const objects missing from object file scott@slp53.sl.home (Scott Lurndal) - 2021-10-09 14:32 +0000
      Re: Global const objects missing from object file Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-09 21:39 +0300
    Re: Global const objects missing from object file Steve Keller <keller.steve@gmx.de> - 2021-10-10 08:55 +0200
      Re: Global const objects missing from object file Bo Persson <bo@bo-persson.se> - 2021-10-10 10:34 +0200
        Re: Global const objects missing from object file Steve Keller <keller.steve@gmx.de> - 2021-10-10 15:55 +0200
          Re: Global const objects missing from object file Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-10 17:28 +0300
            Re: Global const objects missing from object file Steve Keller <keller.steve@gmx.de> - 2021-10-10 20:42 +0200
              Re: Global const objects missing from object file Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-10 22:44 +0300
      Re: Global const objects missing from object file Paavo Helde <myfirstname@osa.pri.ee> - 2021-10-10 12:14 +0300
        Re: Global const objects missing from object file Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-10-29 06:29 -0700
          Re: Global const objects missing from object file Bo Persson <bo@bo-persson.se> - 2021-10-29 15:55 +0200
            Re: Global const objects missing from object file Öö Tiib <ootiib@hot.ee> - 2021-10-29 22:20 -0700
            Re: Global const objects missing from object file Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-11-07 04:51 -0800
          Re: Global const objects missing from object file scott@slp53.sl.home (Scott Lurndal) - 2021-10-29 14:44 +0000
            Re: Global const objects missing from object file Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-11-07 05:08 -0800
              Re: Global const objects missing from object file scott@slp53.sl.home (Scott Lurndal) - 2021-11-07 14:21 +0000
      Re: Global const objects missing from object file David Brown <david.brown@hesbynett.no> - 2021-10-10 12:33 +0200
  Re: Global const objects missing from object file "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-10-09 15:05 +0200
  Re: Global const objects missing from object file Juha Nieminen <nospam@thanks.invalid> - 2021-10-09 17:40 +0000

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