Patch to expand tz checking scope in TimeZone_md.c

[Masayoshi Okutsu]

Probably the difference isn't documented. I tried Solaris 10 and Ubuntu 
10.03. The difference still exists.

Solaris 10:
$ unset TZ
$ date
Fri Nov  4 13:04:45 JST 2011
$ TZ="" date
Fri Nov  4 13:04:53 JST 2011

Ubuntu 10.04:
$ unset TZ
$ date
Fri Nov  4 13:05:50 JST 2011
$ TZ="" date
Fri Nov  4 04:05:55 UTC 2011

When the TZ value is an empty string, Ubuntu uses UTC while Solaris 
still looks up the system default.

Thanks,
Masayoshi

On 11/3/2011 4:16 PM, Jonathan Lu wrote:
> Hi Masayoshi,
>
> I did find some references about date-time related functions / TZ 
> variables on Linux but got only a few about Solaris, so could not see 
> any differences between those two platforms about the changes 
> described in my patch. Have you got any links or references about 
> these differences? I'm interested in it and may update the patch again 
> after reading them.
>
> Thanks a lot!
> - Jonathan
>
> On 11/02/2011 10:27 PM, Masayoshi Okutsu wrote:
>> Hi Jonathan,
>>
>> IIRC, the difference came from some behavioral difference between the 
>> Linux and Solaris libc date-time functions and/or the date command, 
>> and TimeZone_md.c tries to follow the difference. But the code was 
>> written looooong ago. The difference may no longer exist.
>>
>> Thanks,
>> Masayoshi
>>
>> On 11/2/2011 8:39 PM, Jonathan Lu wrote:
>>> On 11/02/2011 07:00 PM, David Holmes wrote:
>>>> On 2/11/2011 7:01 PM, Jonathan Lu wrote:
>>>>> On 11/02/2011 04:56 PM, Jonathan Lu wrote:
>>>>>> Hi core-libs-dev,
>>>>>>
>>>>>> In jdk/src/solaris/native/java/util/TimeZone_md.c, starting from 
>>>>>> line
>>>>>> 626, I found that the scope of "#ifdef __solaris__" might be too
>>>>>> narrow, since it also works for some kind of OS which I'm currently
>>>>>> working on, such as AIX.
>>>>>> So I suggest to just remove the '#ifdef __solaris__' and leave the
>>>>>> "#else" to accommodate more conditions, see attachment 
>>>>>> 'patch.diff'. I
>>>>>> think this may enhance the cross-platform ability, any ideas about
>>>>>> this modification?
>>>>>>
>>>>>> Regards
>>>>>> - Jonathan Lu
>>>>> I'm not sure why the attachment got filtered, here paste it to the 
>>>>> mail
>>>>> content directly.
>>>>>
>>>>> diff -r 4788745572ef src/solaris/native/java/util/TimeZone_md.c
>>>>> --- a/src/solaris/native/java/util/TimeZone_md.c Mon Oct 17 19:06:53
>>>>> 2011 -0700
>>>>> +++ b/src/solaris/native/java/util/TimeZone_md.c Thu Oct 20 13:43:47
>>>>> 2011 +0800
>>>>> @@ -626,10 +626,8 @@
>>>>> #ifdef __linux__
>>>>> if (tz == NULL) {
>>>>> #else
>>>>> -#ifdef __solaris__
>>>>> if (tz == NULL || *tz == '\0') {
>>>>> #endif
>>>>> -#endif
>>>>> tz = getPlatformTimeZoneID();
>>>>> freetz = tz;
>>>>> }
>>>>
>>>> I'm unclear why any of that code needs to be platform specific - is 
>>>> an empty TZ string somehow valid on linux? I would have thought the 
>>>> following would be platform neutral:
>>>>
>>>>    if (tz == NULL || *tz == '\0') {
>>>>         tz = getPlatformTimeZoneID();
>>>>         freetz = tz;
>>>>     }
>>>>
>>> Hi David,
>>>
>>> getenv("TZ") returns NULL when TZ environment variable is not set at 
>>> all and returns '\0' when TZ was exported as empty string. After 
>>> more checking for both cases, I agree with you, nothing useful can 
>>> be retrieved from that environment variable.
>>> So I changed the patch to this,
>>>
>>> diff -r 7ab0d613cd1a src/solaris/native/java/util/TimeZone_md.c
>>> --- a/src/solaris/native/java/util/TimeZone_md.c    Thu Oct 20 
>>> 10:32:47 2011 -0700
>>> +++ b/src/solaris/native/java/util/TimeZone_md.c    Wed Nov 02 
>>> 19:34:51 2011 +0800
>>> @@ -623,13 +623,7 @@
>>>
>>>      tz = getenv("TZ");
>>>
>>> -#ifdef __linux__
>>> -    if (tz == NULL) {
>>> -#else
>>> -#ifdef __solaris__
>>>      if (tz == NULL || *tz == '\0') {
>>> -#endif
>>> -#endif
>>>          tz = getPlatformTimeZoneID();
>>>          freetz = tz;
>>>      }
>>>
>>>> David
>>>> -----
>>>>
>>>>> Regards
>>>>> - Jonathan Lu
>>> Regards
>>>
>>> - Jonathan
>>>
>