Re: Further inconsistencies in FTM

["Alejandro Colomar (man-pages)" <alx.manpages@gmail.com>]

Hi Michael,

On 1/8/21 11:50 AM, Michael Kerrisk (man-pages) wrote:
> Hi Alex,
> 
> On 1/7/21 6:04 PM, Alejandro Colomar (man-pages) wrote:
>> Hi Michael,
>>
>> [[
>> SYNOPSIS
>>        #include <stdlib.h>
>>
>>        int clearenv(void);
>>
>>    Feature   Test   Macro   Requirements  for  glibc  (see  fea‐
>>    ture_test_macros(7)):
>>
>>        clearenv():
>>            /* Glibc since 2.19: */ _DEFAULT_SOURCE
>>                || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
>>
>> ]]
>>
>> [[
>> SYNOPSIS
>>        #include <time.h>
>>
>>        int dysize(int year);
>>
>>    Feature   Test   Macro   Requirements  for  glibc  (see  fea‐
>>    ture_test_macros(7)):
>>
>>        dysize():
>>            Since glibc 2.19:
>>                _DEFAULT_SOURCE
>>            Glibc 2.19 and earlier:
>>                _BSD_SOURCE || _SVID_SOURCE
>>
>> ]]
>>
>> Which one do you prefer?
> 
> Probably the latter, since it is a little easier to read.
> 
> The former form has crept in as a result of my attempts
> to keep the FTM info somewhat compact. See, for example:
> 
>        chroot():
>            Since glibc 2.2.2:
>                _XOPEN_SOURCE && ! (_POSIX_C_SOURCE >= 200112L)
>                    || /* Since glibc 2.20: */ _DEFAULT_SOURCE
>                    || /* Glibc <= 2.19: */ _BSD_SOURCE
>            Before glibc 2.2.2:
>                none
> 
> 
>        waitid():
>            Since glibc 2.26:
>                _XOPEN_SOURCE >= 500 || _POSIX_C_SOURCE >= 200809L
>            Glibc 2.25 and earlier:
>                _XOPEN_SOURCE
>                    || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
>                    || /* Glibc <= 2.19: */ _BSD_SOURCE
> 
> The latter could be rewritten (I hope I got the expansion right) 
> as:
>        waitid():
>            Since glibc 2.26:
>                _XOPEN_SOURCE >= 500 || _POSIX_C_SOURCE >= 200809L
>            Glibc 2.20 to 2.25
>                _XOPEN_SOURCE ||  _POSIX_C_SOURCE >= 200809L
>            Glibc 2.12 to 2.19
>                _XOPEN_SOURCE ||  _POSIX_C_SOURCE >= 200809L
>                    || _BSD_SOURCE
>            Glibc 2.11 and earlier:
>                _XOPEN_SOURCE || _BSD_SOURCE
> 
>  
> That's more verbose, but perhaps also easier to read, now that
> I look at it.
> 
> I'm not sure whether you are thinking of doing some global edit,
> but if you are, perhaps we need to discuss this more.

Well, I'm not thinking of a global edit right now (we've had enough of
those for now I think :), but more as something to think for the future.
So yes, a discussion about if we prefer to have a single way of
expressing FTM or if there are times when the other way is better would
be good.
Your thoughts?

Thanks,

Alex

> 
> Thanks,
> 
> Michael
> 
> 

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/