Re: [PATCH] man: Document ulimit -v

[Gioele Barabucci <gioele@svario.it>]

On 21/01/2016 06:03, Herbert Xu wrote:
> Jérémie Courrèges-Anglas <jca@wxcvbn.org> wrote:
>> Gioele Barabucci <gioele@svario.it> writes:
>>
>>> Document that `ulimit` can set the `RLIMIT_AS` limit (virtual memory) with
>>> the `-v` flag.
>>
>> I don't know much about RLIMIT_AS, but I know that it isn't supported on
>> all systems where dash runs, eg OpenBSD.  Maybe is it Linux-specific?
>>
>> Anyway, it would be better if the manpage said that the -v flag may not
>> be implemented on all platforms.
>>
>> The same could be said about ulimit -w. (I did not check the other flags).
> 
> Rather than doing that we could just pass the manpage through
> cpp or some similar mechanism so that this becomes conditional.

I wonder how much it is worth the effort in this case.

RLIMIT_AS is defined by POSIX [1] since 1997 [2], so one can suppose
that it is available anywhere (indeed the man page of OpenBSD refers to
the missing RLIMIT_AS as a bug). If it is not available, an invocation
of `ulimit -v` will complain about the unknown option. We could just add
to the description "(not available on systems that lack support for
RLIMIT_AS, e.g. OpenBSD)".

Other cases like `-w` can be ignored: they manipulate non-standard
RLIMIT extensions that are no-ops on Linux since long ago (and I suppose
also in other systems).

Regards,

[1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/setrlimit.html
[2] http://pubs.opengroup.org/onlinepubs/7908799/xsh/sysresource.h.html

--
Gioele Barabucci <gioele@svario.it>