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Re: Can a variable be both static and extern

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On 24/03/17 13:14, Richard Bos wrote:

<snip>

> 
> In this example, it's not useful, in fact it would be wrong, to have the
> "static". I could think of a case in which it would be useful, but it
> would have to be a relatively complicated edge case. However, it would
> be possible; and forbidding "static" on the identifiers which can be
> "extern"ed would cause more problems than it would solve.
> 

The example you gave here is just a standard global variable - defined
(and initialised) in one file as "unsigned foo_counter = 1"; and
declared as "extern unsigned foo_counter;" in a header file that is
#included by all files that use it, including the file that defines it.

While it is common to discourage the use of global (cross-module)
variables like this, it is certainly standard practice in C and used
heavily in some types of coding.


The question is, are there any real uses of:

static int foo;
extern int foo;

in the same translation unit (as different headers if you like) ?

I can't think of any myself.  I find it odd that this combination is
allowed - I see no good uses for it, and it could easily occur as a
mistake (especially for people who write "extern" declarations directly
in the their C code, rather than just in headers).

Of course, it could just be my lack of imagination here!

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Thread

Can a variable be both static and extern acidlategamer@gmail.com - 2017-03-24 04:23 -0700
  Re: Can a variable be both static and extern Richard Heathfield <rjh@cpax.org.uk> - 2017-03-24 11:40 +0000
    Re: Can a variable be both static and extern acidlategamer@gmail.com - 2017-03-24 04:54 -0700
      Re: Can a variable be both static and extern Richard Heathfield <rjh@cpax.org.uk> - 2017-03-24 12:09 +0000
        Re: Can a variable be both static and extern James Kuyper <jameskuyper@verizon.net> - 2017-03-24 11:45 -0400
          Re: Can a variable be both static and extern raltbos@xs4all.nl (Richard Bos) - 2017-03-25 22:27 +0000
    Re: Can a variable be both static and extern Keith Thompson <kst-u@mib.org> - 2017-03-24 11:35 -0700
  Re: Can a variable be both static and extern Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-03-24 12:11 +0000
  Re: Can a variable be both static and extern raltbos@xs4all.nl (Richard Bos) - 2017-03-24 12:14 +0000
    Re: Can a variable be both static and extern David Brown <david.brown@hesbynett.no> - 2017-03-24 17:11 +0100
      Re: Can a variable be both static and extern scott@slp53.sl.home (Scott Lurndal) - 2017-03-24 16:22 +0000
        Re: Can a variable be both static and extern David Brown <david.brown@hesbynett.no> - 2017-03-24 17:38 +0100
      Re: Can a variable be both static and extern James Kuyper <jameskuyper@verizon.net> - 2017-03-24 12:23 -0400
        Re: Can a variable be both static and extern David Brown <david.brown@hesbynett.no> - 2017-03-24 17:41 +0100
          Re: Can a variable be both static and extern jameskuyper@verizon.net - 2017-03-24 09:57 -0700
          Re: Can a variable be both static and extern supercat@casperkitty.com - 2017-03-24 10:38 -0700
          Re: Can a variable be both static and extern Richard Heathfield <rjh@cpax.org.uk> - 2017-03-24 18:24 +0000
            Re: Can a variable be both static and extern "James R. Kuyper" <jameskuyper@verizon.net> - 2017-03-25 10:47 -0400
              Re: Can a variable be both static and extern Richard Heathfield <rjh@cpax.org.uk> - 2017-03-25 16:48 +0000
                Re: Can a variable be both static and extern Keith Thompson <kst-u@mib.org> - 2017-03-25 10:31 -0700
                Re: Can a variable be both static and extern Richard Heathfield <rjh@cpax.org.uk> - 2017-03-25 18:23 +0000
                Re: Can a variable be both static and extern supercat@casperkitty.com - 2017-03-25 12:28 -0700
                Re: Can a variable be both static and extern Ike Naar <ike@iceland.freeshell.org> - 2017-03-25 19:50 +0000
                Re: Can a variable be both static and extern supercat@casperkitty.com - 2017-03-25 13:20 -0700
                Re: Can a variable be both static and extern jameskuyper@verizon.net - 2017-03-25 10:44 -0700
                Re: Can a variable be both static and extern supercat@casperkitty.com - 2017-03-25 12:13 -0700

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