zlib configuration : system vs. bundled

[Erik Joelsson]

On 2019-05-15 01:16, Baesken, Matthias wrote:
> Hi Alan,   thanks for pointing me  at the old discussion .
>
> http://mail.openjdk.java.net/pipermail/build-dev/2016-February/016602.html
>
> talks about performance benefits .  Are you aware of some  benchmarks that showed the improvements ?
>
> In reality,  if you have the latest  distro versions you might be lucky and you have a nice recent zlib 1.2.11  .
> However on older distros , you run in reality  into older zlibs  (often I see 1.2.8).  I don't think that this is a very good status .
>
>
> At least I think  building.md  should be fixed to  state the real status , the current  info is wrong :
>
>
> "Certain third-party libraries used by the JDK (libjpeg, giflib, libpng, lcms
> and zlib) are included in the JDK repository. The default behavior of the
> JDK build is to use this version of these libraries, but they might be
> replaced by an external version. To do so, specify `system` as the `<source>`
> option in these arguments. (The default is `bundled`)."
>
>
>
> Btw  how is building.html  generated ,  is this coming from  building.md  ?

Yes, you need to configure with pandoc. Then you run "make 
update-build-docs".

/Erik

> Best regards, Matthias
>
>
>
>
>> -----Original Message-----
>> From: Alan Bateman <Alan.Bateman at oracle.com>
>> Sent: Dienstag, 14. Mai 2019 17:47
>> To: Baesken, Matthias <matthias.baesken at sap.com>; 'build-
>> dev at openjdk.java.net' <build-dev at openjdk.java.net>
>> Subject: Re: zlib configuration : system vs. bundled
>>
>> On 14/05/2019 15:58, Baesken, Matthias wrote:
>>> :
>>>
>>> On the other OS platforms, in case a zlib is found on the system :
>>>
>>>     if test "x${ZLIB_FOUND}" != "xyes"; then
>>>       # If we don't find any system...set default to bundled
>>>       DEFAULT_ZLIB=bundled
>>>     fi
>>>
>>> we use it from the system .
>>> Wouldn't  it be more  consistent to  have  zlib=bundled as well as default for
>> the other UNIX platforms + MacOSX ?
>>> ( people who wish to use  the system zlib still can configure it )
>>>
>>> Otherwise we often run into using old zlib installations at build time which
>> might not be desired.
>> It was a deliberate change in JDK 9 to use the system zlib if possible.
>> Windows is the outlier. If you through the archives of core-libs-dev
>> then you should find several discussions about this, I think the most
>> recent was in 2016, subject line "JDK-8031767 Support system or
>> alternative implementations of zlib".
>>
>> -Alan