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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Alternatives to C (was Re: Safety of casting from 'long' to 'int')
Date: Thu, 14 May 2026 09:55:27 -0700
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scott@slp53.sl.home (Scott Lurndal) writes:

> Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:
>
>> On 2026-05-13 17:12, Scott Lurndal wrote:
>>
>>> We use:
>>>
>>> #  if __GNUC__ >= 7 // 'statement attributes' were new with GCC 7.x
>>> #    if defined(__cplusplus) && (__cplusplus >= 201103L) // C++11 or higher
>>> #      define XXX_FALLTHROUGH [[gnu::fallthrough]]
>>> #    else
>>> #      define XXX_FALLTHROUGH __attribute__ ((fallthrough))
>>> #    endif
>>> #  else // GCC 4.x, 5.x, 6.x, comment only!
>>> #    define XXX_FALLTHROUGH /* Fall Through */
>>> #  endif
>>>
>>> Where 'XXX' is replaced by the app name.
>>>
>>> switch (variable) {
>>> case cond1:
>>>     break;
>>> case cond:
>>>     do something
>>>     XXX_FALLTHROUGH
>>> default:
>>>     do something else
>>> }
>>
>> Just a note aside;  couldn't the XXX be automatically concatenated using
>> the CPP features?  (I seem to recall we've done such things back then.)
>
> Not sure I understand your question.   I used xxx above just
> to obscure the name of the proprietary program that includes
> the above file.
>
>> I also wonder about the app-specific variants;  wouldn't one version for
>> all apps have sufficed?
>
> There is a need  to support gcc4 through gcc14 in that project.  We've
> subsequently raised the lower limit to gcc7.  The project was started
> in 2012.

If instead you use

    #define XXX_FALLTHROUGH  GOHERE_( __LINE__ )
    #define GOHERE_(  n )    GOHERE__( n )
    #define GOHERE__( n )    goto RIGHT_HYAR_##n;  RIGHT_HYAR_##n:

and just give 'XXX_FALLTHROUGH;', how are the results?  It
works fine in my tests.