Re: Cygwin strptime() is missing "%s" which strftime() has

[Brian Inglis <Brian.Inglis@SystematicSw.ab.ca>]

On 2017-07-25 12:52, Corinna Vinschen wrote:
> On Jul 25 10:47, Brian Inglis wrote:
>> On 2017-07-25 03:16, Corinna Vinschen wrote:
>>> On Jul 24 14:41, Brian Inglis wrote:
>>>> On Mon, 24 Jul 2017 02:32:14 -0700, Corinna Vinschen wrote:> On Jul 23 22:07,
>>>>> In this case I have a nit, but this should be discussed on the right
>>>>> mailing list so all affected parties can chime in.  Hint: strtoimax is
>>>>> not available on all platforms yet (patches still in limbo)...
>>>>
>>>> Figured there would need to be some tweaks for newlib platforms, compilers, and
>>>> style, so made some changes, attached another diff for discussion, before
>>>> submitting a patch.
>>>> Let me know if you want conditionals or declarations changed, hoisted to
>>>> function start, case braces removed, other issues?
>>> [...]
>>>> +	    case 's' : {
>>>> +#if defined(INTMAX_MAX)
>>>> +#  define BIG_T		intmax_t
>>>> +#  define STRTOBIG	strtoimax
>>>> +#elif defined(LLONG_MAX)
>>>> +#  define BIG_T		long long
>>>> +#  define STRTOBIG	strtoll
>>>> +#else
>>>> +#  define BIG_T		long
>>>> +#  define STRTOBIG	strtol
>>>> +#endif
>>>
>>> I don't think we need to use intmax_t at all here.  Checking for
>>> LLONG_MAX should be sufficient.  However, this is strptime_l.  so you
>>> should use strtoll_l/strtol_l, just like the rest of the function.
>>>
>>> On second thought, do we have to do this at all?  Our time_t is always
>>> long anyway so using just strtol_l and checking for ERANGE should be
>>> sufficient:
>>>
>>>   int old_errno = _REENT->_errno;
>>>   sec = strtol_l (buf, &s, 10);
>>>   int new_errno = _REENT->_errno;
>>>   _REENT->_errno = old_errno;
>>>   if (s == buf || new_errno == ERANGE || etc...
>>>
>>>> +		    BIG_T sec;
>>>> +		    time_t t;
>>>> +
>>>> +		    sec = STRTOBIG (buf, &s, 10);
>>>> +		    t = (time_t)sec;
>>>> +		    if (s == buf
>>>> +			|| (BIG_T)t != sec
>>>> +			|| localtime_r (&t, timeptr) != timeptr)
>>
>> Is time_t always long on all newlib platforms, or could it be long
>> long in some environments/memory models e.g. Windows 64 VS/MinGW
>> LLP64/IL32P64 vs Cygwin/Unix LP64/I32LP64?  Could/should we keep the
>> strtol[l] options and use the ..._l variants?
> 
> Well... on *third* thought, targets may redefine time_t via redefining
> _TIME_T_.  Targets not doing that will get long, so yeah, you're right.
> Maybe it is safer to use always strtoll_l and just break this down to
> time_t on the way.

My concern has always been do all newlib RTEMS targets support long long, even
if same as long, and stroll_l?

>> Can't we just use errno, as shouldn't that be mapped to _REENT->_errno
>> in this context if required, or can it/does it need to be explicit?
>> These are locale-dependent ..._l functions not reentrant ..._r
>> functions, and there is no "#include <reent.h>"?
> 
> No, I was just trying to be thorough.  errno is fine, just include
> errno.h.
> 
>> Don't we need to save and zero errno to distinguish a new error, and
>> restore if it stays zero, rather than just pick up the current value,
>> and assume if it is/was ERANGE it's bad?
> 
> Right, I forget that when I typed the above.
> 
>>> Shouldn't this be gmtime_r?
>>>
>>>  %s     The number of seconds since the Epoch, 1970-01-01 00:00:00 +0000
>>> 	(UTC).  Leap seconds are not counted unless leap second  support
>>> 	is available.
>>
>> The input is seconds since the epoch, but the interpretation in struct
>> tm depends on the locale, so we use localtime_r(3).  The timezone may
>> be set in the environment or locale, and may be UTC.  If you want
>> gmtime/UTC you set TZ=UTC0, TZ=Etc/UTC, which should override/change
>> locale LC_TIME, as would setting %z with value +0000 or %Z with values
>> UTC or Z, where that is supported by strptime_l(3) (i.e. not here).
> 
> Hmm, yes, ok, that makes sense.

K will change and check and format-patch.

Trying to build standalone or combined STC for this with changed strptime.c
ld/collect2 fails to resolve ...global_locale.
Of course STC alone builds and fails properly with current release.
Is there anything I can include or add somewhere to get this to build - recent
dev snapshot maybe?

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada