On Fri, Dec 18, 2015 at 5:35 AM, Magnus Ihse Bursie <magnus.ihse.bur...@oracle.com> wrote: > On 2015-12-15 18:25, Martin Buchholz wrote: >> >> _FILE_OFFSET_BITS is generally an all-or-nothing thing, because it >> affects interoperability between translation units. It would be good >> to convert all of the JDK build to use -D_FILE_OFFSET_BITS=64, but >> that would be a big job. So traditionally the JDK has instead used >> the functions made available via _LARGEFILE64_SOURCE. But that is >> also a JDK-wide job now, because every call to plain stat in the >> source code is broken on 32-bit systems with 64-bit inodes, which are >> becoming more common. >> >> I recommend the _FILE_OFFSET_BITS=64 strategy, but it's probably a job >> for build-dev, not core-libs-dev. > > > If I understand things correctly, then setting _FILE_OFFSET_BITS=64 would > mean two things: > 1) Just pass this additional define to all C files being compiled (a build > change) > 2) Update all calls to file operating functions to make sure the proper > 64-bit types are used (changes in source code). > > The change for 1) is a trivial one liner, while getting 2) correct is a > serious undertaking in the source code.
If everyone is properly pairing up their function calls with proper types (i.e. using off_t consistently), then everything should Just Work. Such a change must be done by the > component teams, not the build team. I think this is an openjdk cultural problem - changes like this can and should be done by one person, with help from component teams where necessary. It's safer to add _FILE_OFFSET_BITS=64 everywhere at once (although hotspot and libraries can probably be cleanly separated) to avoid type size disagreement between translation units. For bonus points, we can later change all of those *64 functions back to their standard equivalents. With that said, I think it is a > reasonable change and I'll support it as much as I can. But as the division > of labour is done here, it's not the work of the build team to go and make > heavy modifications to the product source code.
