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Re: The variable __func__ in C89 in gcc

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Tim Rentsch <txr@alumni.caltech.edu> writes:
> Seebs <usenet-nospam@seebs.net> writes:
[...]
>> __func__ is in the implementation's namespace.  There is no lack of
>> compliance with C89 if the implementation happens to define things in
>> its own reserved namespace...
>
> The problem is the Standard doesn't say that.  The Standard talks
> about 'reserved identifiers', not an 'implementation namespace'.
> "Reserved" means a program may not declare or define them (modulo
> section 7.1.7).  The section that specifies which identifiers are
> reserved (which is 7.1.3) says that they may be declared or
> defined in _header files_ (clearly not relevant for __func__),
> but AFAICS nothing otherwise.  In the absence of any provision
> allowing the implementation itself (as opposed to a header file)
> to declare or define reserved identifiers, I don't see why we
> should suppose that it's allowed to.  And of course that would
> mean that '__func__' would cause a syntax error, triggering a
> diagnostic.
>
> It's quite plausible that the original intention was to allow
> implementations to define reserved identifiers however they like.
> I just don't see any text in the Standard that grants such a
> right.

Quibble: It would be a constraint violation, not a syntax error, but
that doesn't affect the argument.

C99 5.1.1.3 explicitly states that violations of syntax rules and
constraints must be diagnosed even in the presence of undefined
behavior.  C90 5.1.1.3 does not, and the possible consequences of
undefined behavior include "behaving during translation or program
execution in a documented manner characteristic of the environment
(with or without the issuance of a diagnostic message)" (C90 3.16).

But we're still left with the question of whether a conforming C99
implementation may predefine __foo__ (not in any header).  Like you,
I'd say that the intended answer s yes, but I can't prove it from
the standard.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Nokia
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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The variable __func__ in C89 in gcc rouben@shady.(none) (Rouben Rostamian) - 2011-05-18 14:08 +0000
  Re: The variable __func__ in C89 in gcc Shao Miller <sha0.miller@gmail.com> - 2011-05-18 10:13 -0400
  Re: The variable __func__ in C89 in gcc Seebs <usenet-nospam@seebs.net> - 2011-05-18 16:03 +0000
    Re: The variable __func__ in C89 in gcc Keith Thompson <kst-u@mib.org> - 2011-05-18 10:32 -0700
      Re: The variable __func__ in C89 in gcc cri@tiac.net (Richard Harter) - 2011-05-18 19:39 +0000
        Re: The variable __func__ in C89 in gcc Seebs <usenet-nospam@seebs.net> - 2011-05-18 19:45 +0000
      Re: The variable __func__ in C89 in gcc William Ahern <william@wilbur.25thandClement.com> - 2011-05-18 19:27 -0700
    Re: The variable __func__ in C89 in gcc Keith Thompson <kst-u@mib.org> - 2011-05-19 08:42 -0700
      Re: The variable __func__ in C89 in gcc Seebs <usenet-nospam@seebs.net> - 2011-05-19 16:34 +0000
        Re: The variable __func__ in C89 in gcc Kenneth Brody <kenbrody@spamcop.net> - 2011-05-19 14:15 -0400
        Re: The variable __func__ in C89 in gcc Shao Miller <sha0.miller@gmail.com> - 2011-05-19 14:45 -0400
        Re: The variable __func__ in C89 in gcc Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-19 14:02 -0700
      Re: The variable __func__ in C89 in gcc Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-19 12:45 -0700
  Re: The variable __func__ in C89 in gcc Sorc Chan <sorcchan@gmail.com> - 2011-05-19 02:03 -0700
    Re: The variable __func__ in C89 in gcc James Kuyper <jameskuyper@verizon.net> - 2011-05-19 06:17 -0400
      Re: The variable __func__ in C89 in gcc Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-19 13:44 -0700
        Re: The variable __func__ in C89 in gcc Keith Thompson <kst-u@mib.org> - 2011-05-19 13:48 -0700
          Re: The variable __func__ in C89 in gcc Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-19 14:12 -0700
            Re: The variable __func__ in C89 in gcc Keith Thompson <kst-u@mib.org> - 2011-05-19 14:29 -0700
              Re: The variable __func__ in C89 in gcc gazelle@shell.xmission.com (Kenny McCormack) - 2011-05-19 21:54 +0000
                Re: The variable __func__ in C89 in gcc Angel <angel+news@spamcop.net> - 2011-05-19 22:27 +0000
              Re: The variable __func__ in C89 in gcc Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-24 02:23 -0700
          Re: The variable __func__ in C89 in gcc gazelle@shell.xmission.com (Kenny McCormack) - 2011-05-19 21:54 +0000
          Re: The variable __func__ in C89 in gcc James Kuyper <jameskuyper@verizon.net> - 2011-05-19 23:26 -0400
            Re: The variable __func__ in C89 in gcc Shao Miller <sha0.miller@gmail.com> - 2011-05-19 22:39 -0500
    Re: The variable __func__ in C89 in gcc Shao Miller <sha0.miller@gmail.com> - 2011-05-19 08:22 -0400
      Re: The variable __func__ in C89 in gcc Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-19 13:47 -0700

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