RFR: JDK-8152545: Use preprocessor instead of compiling a program to generate native nio constants

[Alan Bateman]

On 23/03/2016 16:14, Erik Joelsson wrote:
> :
>
> On 2016-03-23 12:13, Erik Joelsson wrote:
>> There are however 3 that, at least on Linux, are defined as an enum 
>> and not constants, which makes them unavailable to the preprocessor. 
>> These are:
>>
>> IPPROTO_TCP = 6
>> IPPROTO_IP = 0
>> IPPROTO_PV6 = 41
>>
>> I would say that this is fine. They have the same value on all our 
>> supported platforms and are actually part of the IP spec. I cannot 
>> imagine a reason for ever defining them differently. So the solution 
>> is to simply define these as constants in the java source.
>>
>> By fixing this, cross compiling new or existing platforms becomes 
>> much easier.
>>
>> I have verified this patch by manually comparing the output and by 
>> running the jdk_nio tests in JPRT.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8152545
>> Webrev: http://cr.openjdk.java.net/~erikj/8152545/webrev.jdk.01/

The hard coded values should be okay because they are standard, for 
example RFC 2292 defines IPPROTO_IPV6 as 41, TCP is protocol number 6.

Is the #undef sun really needed? It otherwise looks good to me. We can 
fix up the very long lines at some point to get it consistent with the 
other code in this area.

-Alan.