Re: Fwd: [Rd] [musl] strptime() question

[Alba Pompeo <albapompeo@gmail.com>]

It is setting TZ and using tzset(). R is not multi-threaded so it is safe.

Simon figure out the important settings from the config.log and
config.h files on a musl system:

/* #undef USE_INTERNAL_MKTIME */
#define HAVE_TM_GMTOFF 1
#define HAVE_TM_ZONE 1

Does this help anyone debug the issue? Simon just went on vacation.



On Thu, Feb 4, 2016 at 7:32 PM, Rich Felker <dalias@libc.org> wrote:
> On Thu, Feb 04, 2016 at 04:35:22PM -0200, Alba Pompeo wrote:
>> I forwarded our talk on musl mailing list to R mailing list.
>> I got this response.
>> Does it help?
>> Also, what do you think about making a new email that's sent to both
>> musl and R mailing list, that way devs from both projects can
>> communicate? It's a tad inefficient for me to keep forwarding messages
>> like this back and forth.
>
> I'm cc'ing both lists now.
>
>> ---------- Forwarded message ----------
>> From: Simon Urbanek <simon.urbanek@r-project.org>
>> Date: Thu, Feb 4, 2016 at 3:01 PM
>> Subject: Re: [Rd] [musl] strptime() question
>> To: Alba Pompeo <albapompeo@gmail.com>
>> Cc: r-devel <r-devel@r-project.org>
>>
>>
>>
>> On Feb 4, 2016, at 11:20 AM, Alba Pompeo <albapompeo@gmail.com> wrote:
>>
>> > There is incompatibility between R strptime and musl libc. I posted
>> > about it on their mailing list, but they need more information I can't
>> > provide, so I'm forwarding the message here in hope R developers can
>> > help. Thanks.
>>
>> Generally, it's using the standard tzset() call to set the time zone
>> http://pubs.opengroup.org/onlinepubs/009695399/functions/tzset.html
>
> The tzset function doesn't really do much interesting; it just updates
> some global state to match the current value of the TZ environment
> variable, but most time.h functions do this already anyway. Anyway
> this doesn't really answer the question of what R's strptime function
> is doing to add timezone functionality onto the underlying system's
> strptime. Is R changing the environment (this is highly unsafe in any
> potentially-multithreaded process, BTW)? Is it using the globals set
> by tzset to compute adjustments to the result?
>
> Rich