On 27 Dec 2015, at 10:08pm, Olivier Mascia <om at integral.be> wrote:
> What I don't really get straight is what file-locking related mechanism would > have a use for those bytes, knowing they wouldn't even exists unless the > database size is 2^30 bytes or more? Some operating systems for unusual operating systems or embedded devices use file APIs which top out at 2^30 bytes (signed integer 32 bits long). They have great difficulty in handling database which are longer than that many bytes, including trying to simulate locks on parts of those files. These bytes can be used by a VFS designed to run on those operating systems to allow communication between processes about lock status. If you are not writing your own VFS to run in a 31-bit file system then you should avoid using these bytes. This includes cases where you're not writing a VFS and cases where your VFS runs on a normal multipurpose desktop computer with a 32-bit or 64-bit file system. Simon.
