Re: [hackers] [farbfeld] arg.h: Refactor ARGF_() || Laslo Hunhold

From: Michael Forney <>
Date: Fri, 4 Aug 2017 09:18:47 -0700

On 8/4/17, Richard Ipsum <> wrote:
> On Fri, Aug 04, 2017 at 08:37:14AM -0700, Michael Forney wrote:
>> You can't use identifiers that begin with '_', they are reserved for
>> the C implementation:
>> "All identifiers that begin with an underscore are always reserved for
>> use as identifiers with file scope in both the ordinary and tag name
>> spaces."
> This crossed my mind as well, but then we notice that these aren't
> defined in file scope. If you have two underscores however that's
> reserved regardless of use.
> "In addition to the names documented in this manual, reserved names include
> all external identifiers (global functions and variables) that begin with an
> underscore (‘_’) and all identifiers regardless of use that begin with
> either two underscores or an underscore followed by a capital letter are
> reserved names. This is so that the library and header files can define
> functions, variables, and macros for internal purposes without risk of
> conflict with names in user programs."[1]

Well, I guess these local variables could shadow a file-scope variable
used by the C implementation, but I think it's better to avoid the
names all-together. We wouldn't want to accidentally use the
file-scope variable if a variable was renamed, but missed in one spot.

> Thanks,
> Richard
> [1]:

I think we should refer the C standard rather than the glibc manual
(though in this case they say essentially the same thing).

> --
> Life is too short for POSIX compliance
Received on Fri Aug 04 2017 - 18:18:47 CEST

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